Keeping The Heat In - Section 9: Operating your house: thermostats, water heaters, furnaces and other heating/cooling systems

Like any system, your house will run only as efficiently as you operate and maintain it. Operating it efficiently will maximize your retrofit gains and can actually improve your home's heating, cooling and ventilation performance and overall durability. Even more important, you will create a healthier, more comfortable living environment. As part of your house as a system, a well-tuned and efficiently operating heating, ventilating and air-conditioning (HVAC) system can significantly reduce your annual energy bill.

Summary

• 9.1 Operating and maintaining the heating, ventilating and air-conditioning system
• 9.2 Domestic hot water
• 9.3 Cooling systems
• 9.4 Ventilation and combustion air
• 9.5 More ways to save energy

9.1 Operating and maintaining the heating, ventilating and air-conditioning system

Follow the manufacturer’s recommended maintenance procedures for cleaning and servicing heating and cooling equipment. Oil-fired furnaces and boilers require annual cleaning and tuning. Natural gas and propane furnaces and boilers and ground-source heat pumps should be serviced at least every two years. If your home has solid fuel burning equipment (for example, wood stove or fireplace), have the equipment and chimney inspected annually and cleaned as often as necessary. 

9.1.1 Homeowner maintenance

Although a qualified service technician should perform annual maintenance and efficiency tune-ups, homeowners can do some of the work.

Safety warning:

Building codes now require that every home with a combustion appliance or attached garage must have a carbon monoxide (CO) detector, one located near the furnace or appliance or one within 5 m (15 ft.) of each bedroom door. Typically, the requirement is to have one detector located near the furnace or appliance and one detector in each bedroom area to ensure that the alarm can be heard. Be sure to follow the installation and operation instructions. Check with your building or fire department for more information.

For a forced-air system, keep return-air grilles and warm-air vents clean and free of obstructions, and change or clean filters every three months or as they become loaded. Vacuum the radiators of electric or hydronic baseboard systems each autumn to prevent dust buildup. If the heating fins are bent, gently straighten them with a plastic comb to improve their efficiency.

Hydronic systems perform best when radiators are relatively free of air bubbles and operating at correct pressures. This means bleeding radiators regularly unless the system has an automatic bleeding capability. Automatically achieve further savings with an outdoor reset control that adjusts the operating temperature of the circulating water according to outdoor temperatures.

9.1.2 Thermostats

Except for some hydronic systems and heat pumps with slow response times, you can save energy by turning down your thermostat, and the best way to do this is to install a programmable setback thermostat. A basic programmable thermostat will provide a clock timer and allow at least two setback and reset periods a day.

For example, a temperature reduction could be programmed to start before bedtime and end before you get up in the morning. The second setback can reduce the temperature when everyone is away during the day and end just before you arrive in the evening.

A drop of 1°C (2°F) over an eight-hour period can save about 2 percent on your heating energy consumption. If you are away from home for more than three or four hours, it is worthwhile to turn down the temperature. In general, it is best not to reduce the temperature lower than 17°C (63°F), as there is a risk of moisture build-up in the exterior walls. If you want to reduce your temperature further, such as when you are away for extended periods of time (a week or longer), you must keep humidity levels low (see Part 2.4, Control of moisture flow).

Measure the relative humidity throughout the house with a hygrometer to ensure low levels exist, and if not, reduce the humidity by controlling moisture sources or by adding an ENERGY STAR^® certified dehumidifier.

Smart thermostats are also available that allow you to control home heating and cooling remotely through your smartphone, computer or tablet. They may also provide home energy use information for tracking and management.

A subset of smart thermostats are adaptive thermostats. They can monitor weather, occupancy or proximity to a home and establish an accurate schedule. They will adapt heating and cooling to suit your needs and provide even greater savings over programmable thermostats.

9.1.3 Sizing and balancing an HVAC system

A newly retrofitted house will have reduced heat loss and will need a smaller heating and cooling system than before the retrofit. This means that any fuel-fired heating equipment may now be oversized – a condition that can cause larger temperature fluctuations and inefficient short cycling, especially for mid-efficiency furnaces and boilers. High-efficiency furnaces and boilers are less affected efficiency-wise, but temperature fluctuations will still affect comfort for occupants, and the equipment will suffer more wear and tear.

When a mid-efficiency furnace or boiler operates less often, the chimney can get colder between firings, increasing the potential for down drafting and possible condensation and damage to the chimney. If your retrofit measures are extensive and you are concerned about this, have the system checked by a qualified heating-system technician.

If the short cycling problem cannot be controlled or comfort becomes an issue, consider replacing the furnace with a high efficiency 2-stage, 3-stage or fully modulating unit. Modulating boilers are also available with outdoor reset controls that further improve a boilers energy efficiency by reducing the boiler water supply temperature. Staged and modulating furnaces and boilers have the advantage of being able to run very efficiently at lower firing rates especially in the spring and fall as well as during less intense cold periods of winter. For example, in milder weather, a 2-stage furnace may fire at 60% and 100% of its rated capacity, a 3-stage furnace might fire at 60%, 75% and 100% and a modulating unit may fire at any point from 60% to 100%. This greater control allows the unit to provide consistent lower heating output levels over a longer time, instead of an intermittent higher heating output level over a shorter time. This results in increased occupant comfort while allowing the equipment to run efficiently without short cycling (such as in its peak efficiency band).

In addition, while the unit is operating at steadier and lower capacity, more air passes through the air filter which leads to better indoor air quality.

A persistent problem for almost all new, existing and renovated homes is the need to have the heat distribution system balanced. Undersized ductwork, leaking ducts, inadequate or poorly placed return air grilles and ducts can mean occupant discomfort and higher heating bills. Improved insulation and air sealing may make some previously hard-to-heat rooms easier to heat, while others may overheat.

Simple rebalancing of the system by either adjusting the dampers in a ducted system or adjusting valves in a hot water system may help. Otherwise, find a competent contractor to upgrade or balance your system. Be warned, duct cleaning alone will not resolve balancing issues and generally has little effect on the HVAC system and indoor air quality. For more information on duct work and duct balancing see Part 9.3.1, Balancing an air conditioning system.

Be warned, duct cleaning alone will not resolve balancing issues and generally has little effect on the HVAC system and indoor air quality.

9.1.4 Motor Selection

When selecting a furnace, a boiler, a heat or energy recovery ventilator (HRV or ERV), the types of fan or pump motor(s) in these pieces of equipment will have an impact on the overall efficiency of the unit. The two main types of motors available on the market today are permanent split capacitor (PSC) and direct current brushless motors (commonly referred to as ECM for electronically commutated motor).

PSC motors typically operate at 60% to 65% efficiency at peak capacity and become less efficient when they are programmed to run at lower speeds. They tend to start and stop abruptly and have limited speed change options with little associated energy savings. They can also get very hot which is a major disadvantage if using the furnace for cooling or air conditioning.

Alternatively, ECMs can be programmed to run with a much greater range of speeds, can start and run quietly even when increasing or decreasing speed, and their efficiency stays high (near 80%) even if their speed is reduced. In addition, ECMs operate much cooler and have other features like ability to meet the airflow required even when dust filters and dirty air conditioning coils cause restrictions.

It is worth noting that while ECM motors can overcome resistance in the duct system such as dirty filter or restrictive ductwork, they consume more power to do so. Good duct design, wise filter selection and regular cleaning and filter changes all contribute to an efficient heating and cooling system.

9.1.5 Air distribution ducts

To improve comfort, safety and system balancing, seal all plenums and supply and return ducts with aluminum foil duct tape, approved flexible plastic tape or water-based mastic. Heating ducts running through unheated or cool basements and crawl spaces should be insulated. Cut RSI 2.1 (R-12) or more of batt or blanket insulation to size or use specially designed foil-faced fibreglass blanket insulation designed for this purpose. Wrap the insulation around the ducts and secure with string, zip ties or approved tape (see Figure 9-1). Do not use standard vinyl type duct tape for duct sealing or securing insulation around ducts as the adhesive dries out over time and the tape falls off.

Do not seal or wrap the ducts within 1.8 m (6 ft.) of a wood-fired furnace unless you use a special, approved non-combustible tape, mastic, or insulation.

Another option is to seal ducts from the interior using a blown-in plastic polymer that seals all joints, gaps and holes typically 10 mm (3/8 in.) or smaller. This process is done by a qualified technician using specialized equipment. The technician will temporarily seal off sections of the duct work to exclude the furnace and air conditioner, and plug the existing supply registers and return grilles. The blown-in sealant will collect and bond to the edges of the duct where air is leaking, ultimately sealing the gaps.

For houses with hydronic systems, place foil-covered insulation board between radiators and exterior walls to reflect heat back into the room. Metallic supply and return lines can be insulated with minimum RSI 0.7 (R-4) approved insulation. Insulated jackets are available for some types of boilers and may offer some efficiency gains for equipment installed in cold parts of the house.

9.1.6 Open hearth fireplaces

Open hearth gas- or wood-fired fireplaces are basically decorative; the heat supplied will not make up for the losses due to house air drawn up the chimney. Consequently, most fireplaces are unable to provide any net heat gain. Fireplace accessories such as tightly fitted glass doors only offer nominal improvements on efficiency. The hearth industry has a variety of efficient direct vent zero-clearance fireplaces and inserts: gas, propane, pellet and wood units that also look great and eliminate standby losses. Refer to Part 4.2.5, Tips on sealing some of the leakiest areas - Fireplaces and Figure 4-6 for tips on how to reduce air leakage from an unused fireplace.

9.2 Domestic hot water

Domestic water heaters (DWHs) consume on average about 20 percent of a home’s energy – about the same as all the lights and appliances combined. Next to space heating, the water heater is the largest energy user in most homes. In comparison, in a substantially renovated or new energy efficient home the DWH load can be greater than the space heating load.

9.2.1 Replacing your fuel-fired DWH system

The best energy performance option is to replace the existing system with a new high-efficiency system, including tank-type, instantaneous or combination space and water heating models. Compare carefully for your best selection. Match the size of the heater to your needs: bigger tank-type units are typically less efficient than smaller units, especially if your hot water demand is low. Use sizing charts available from the manufacturer or retailer. If considering the installation of an on-demand water heater, wait times for hot water delivery at the fixture will likely increase. Discuss with your plumber how to reduce the wait time and any resulting wasted water.

There are more energy-efficient options now available, including ENERGY STAR^® certified DWH units and solar hot water heating systems. Find the most energy-efficient model for your needs.  

Energy saving tips for DWH systems

Here are some ways to save on hot water bills:

• Use less hot water: fix leaks and drips, wash clothes in cold water, use low-flow showerheads and restrictive aerators on faucets.
• Locate the water heater close to point-of-use or use small-diameter piping and run it directly from the tank to each point-of-use.
• If the point-of-use is 9 m (30 ft.) or more from the water heater, install a demand-type hot water recirculation system that can operate with or without a return line to the DWH.
• Install an insulated base and an insulating kit around the tank for electric tank type water heaters located in basements.
• Insulate both metallic and plastic water lines with a minimum of RSI 0.7 (R-4) compatible insulation (such as pre-formed type).
• Install a drain water heat recovery unit on the main vertical or horizontal stack(s) serving the shower(s).
• Install a solar water heater to pre-heat the water for the DWH system.

9.3 Cooling systems

Although Keeping the Heat In publication is about keeping your home warm and comfortable, air conditioning is becoming more common across Canada and is briefly discussed here.

Retrofitting also reduces the amount of energy needed to cool your home in the summer. Air conditioning lowers both air temperature and, very importantly, humidity levels. Air conditioning is a good example of where oversizing is clearly detrimental to comfort, cost of operation and equipment performance. An oversized system will lower house temperature too quickly without removing excess humidity. The result is a house that is cool and damp, which in turn can promote mold growth and musty odors. Higher indoor temperatures (for example, 26°C/79°F) with reduced humidity levels are more comfortable and allow for more energy savings.

Air conditioners should be serviced and maintained regularly. They become inefficient when the inside coil is dirty, when the airways on the outdoor condenser unit are blocked and when the refrigerant level runs low. You can do some simple maintenance yourself.

For example, clean or change the air filter, keep the outside condenser free from obstructions such as plants and leaves. In addition, a service contractor should periodically maintain your unit. Check your owner’s manual for information on maintenance.

9.3.1. Balancing an air conditioning system

In a multi-story home, it is not uncommon to experience hotter temperatures on the upper levels during the cooling season. This is because the upper walls and ceilings are typically exposed to more solar heat gains which is further aggravated by the fact that warm air rises. In addition, the ducting for most central heating and cooling systems is designed primarily to satisfy the heating requirements and is controlled by one thermostat located on the main floor. This means that when the air temperature near the thermostat meets the desired thermostat setting, the second floor will still be too warm, and the basement will likely be too cold. It is possible to make some manual adjustments with dampers located in the ductwork to help even out the temperatures throughout the house (if not installed, dampers can be added in many cases by a heating/cooling technician). 

You can try to partially close some of the dampers in the basement and on the main floor and leave the dampers fully open on the upper levels. The intent is to create a balanced air distribution system for summer cooling and a different balanced system for winter heating by just adjusting the dampers. If no dampers are installed or can be accessed, individual registers can also be adjusted but they are less effective than controlling the air in the ducts. Placing thermometers on the different levels can assist with the manual adjustments as it will take some trial and error before possibly finding a balance that works best. If you find your attempts to balance the system are ineffective, it may be because the ductwork is too leaky. In this case, closing the dampers may just cause more leakage rather than sending the air to the intended room.

Balancing a system won’t always work if there is insufficient return air ducting or inadequate supply ducts.  In these cases, a separate ductless mini-split air conditioner on the upper floors can help to resolve the problem (installing a higher capacity or more efficient air conditioner will in most cases not resolve the problem and can actually make it worse). Alternatively, in some homes a large duct can be installed from the basement to the upper floor as a means to help return hot stale air trapped in the upper portion of the house down into the basement where it is connected to the main return ductwork to the furnace. Finding a suitable location for the duct can be a challenge and, in some cases, an inline fan may be required to help draw the hot air down and into the furnace.

In every case when balancing a system, mark the position of any dampers before making adjustments, and then mark the best positions for both summer and winter. Be careful not to restrict air supply back to the furnace as this can result in freezing the air conditioning coil (not harmful to the coil) located in the furnace plenum (chamber typically just above the furnace) or cause the furnace to shut down in the heating season by triggering the furnace’s high heat limit switch. Do not hesitate to discuss your concerns with your heating and cooling maintenance technician.

There might be other solutions for balancing a system such as adding a separate heating or cooling system per floor. You can discuss options that can work in your home with an HVAC professional.

9.3.2. Portable air conditioners

If you are considering getting a portable air conditioner (PAC) to help cool a small area of your home, choose wisely as these units are in general not very efficient because the entire unit is indoors. First, avoid single-hose PACs as they are least effective. As single hose units draw warm air from the room and exhaust the heat outdoors, they create a negative pressure that causes more hot humid outdoor air to leak into the home. This results in the air conditioner operating for extended periods of time while trying to meet the desired temperature. This means more power consumption, higher energy bills and prolonged operating noise. A better alternative is a dual-hose PAC that can cool space quickly without exhausting indoor air outdoors. Dual-hose PACs have an additional hose that draws in air from the outside.  This air passes through the compressor and the air conditioner’s coil capturing the heat and exhausts it out the other hose to the outside. This results in no negative pressure indoors and increased overall cooling capability.

9.4 Ventilation and combustion air

People need fresh ventilation air to control indoor air quality, and fuel-fired space and water heating systems need combustion air to burn properly. Yet, most Canadian homes have too much excess air due to poorly sealed building envelope. In fact, typically about 25 percent of heat loss can be due to air leakage.

For most older homes, comprehensive air leakage control will lower heating bills without reducing the air supply enough to cause problems. Air leakage does not make for good ventilation.

A better approach is to install a ventilation system that is capable of changing the total household air once every three hours, plus providing separate combustion air for fuel-burning appliances.

Take a systematic look at the moisture balance and ventilation needs of your house. This involves listing moisture sources, symptoms of problems and ventilation requirements. Figure 9-2 lists some common sources of moisture. Retrofits will affect the house, so if the house already shows signs of excessive condensation, find and reduce the moisture sources. If this cannot be done, any retrofit that makes the house more airtight will have to include a mechanical ventilation system.

Some systems exhaust stale air, some exhaust stale and supply fresh air and some are balanced to do both. The addition of balanced ventilation with heat recovery has a long list of benefits including ability to control the rate of ventilation, maximizing air tightening and increased home durability. Furthermore, improved indoor air quality from controlled ventilation has proven positive health effects.

9.4.1 Is your house susceptible to indoor air quality problems?

Be aware of potential problems, the symptoms to look for and some of the possible solutions. The following circumstances can make a house more susceptible:

• Houses without a conventional chimney and/or a circulating air duct system.
• Competition for air from fireplaces and/or powerful exhaust vents such as kitchen range hoods.
• Non-ducted range hoods or undersized or inoperable bathroom fans.
• Air sealing a home without adequate ventilation.
• Sources of air contamination (smokers, burning candles, hobbies, etc.).
• High humidity levels.
• High radon levels (see Part 1.4, Health and safety considerations).

9.4.2 Some signs of indoor air quality and moisture problems

The following symptoms indicate that your house may have air quality or moisture problems:

• Excessive condensation on double-paned windows.
• Staining and mould growth, which often appears in bathrooms, closets and on walls or ceilings situated on exterior walls.
• Stuffy, musty atmosphere and lingering odours.
• Back-puffing and odours from the space and water heating equipment.
• Backdrafts of combustion gases or odours from the fireplace.

9.4.3 Solutions to moisture problems

If the problem is high humidity or condensation, the first step is to reduce the amount of water vapour in the air:

• Do not store firewood in the house.
• Avoid drying laundry in the house.
• Vent the clothes dryer to the exterior.
• Disconnect any humidifiers.
• Cover exposed earth floors in basements or crawlspaces with a moisture barrier.
• Install a sump pump with a cover to remove excess moisture from the soil under the slab.
• Fix all water leaks into the basement.
• Do not allow any standing water in the house or against the foundation wall.
• Make sure the ground slopes away from the foundation wall and that there are properly functioning eavestroughs around the house (see Figure 2-12).
• Operate kitchen and bathroom fans during use.
• Adjust your living habits to produce less humidity (cleaning, washing, number of houseplants and aquariums, etc.).

Table 9-1 shows the maximum levels of indoor relative humidity at 21ºC (70ºF) at which there will be no condensation on conventional double-glazed or energy-efficient windows at various outside temperatures.

Table 9-1 Maximum indoor relative humidity levels

Outdoor temperature	Maximum indoor relative humidity
	Older generation double-glazed low-E	Double-glazed	Double-glazed low-E	Triple-glazed low-E
0°C (32°F)	50%	58%	70%	81%
-10°C (14°F)	34%	44%	59%	74%
-20°C (-4°F)	24%	34%	50%	67%
-30°C (-22°F)	15%	25%	42%	60%
-40°C (-31°F)	10%	18%	35%	54%

It can be difficult to accurately measure and maintain the recommended humidity levels. One simple approach is to let your windows become your indicator. If excessive condensation appears on the interior surface of double-glazed windows (except those in the kitchen and bathroom), you have too much moisture in the air. Alternatively, you can also use a hygrometer to monitor humidity levels.

Occasional condensation does not pose a problem. Excessive condensation or frosting is an indication that you should reduce moisture production or increase ventilation. Refer to the Health and safety considerations for energy-efficient renovations of our website.

Finally, if you are replacing your space heating and DWH systems with high-efficiency sealed combustion equipment, this may affect indoor air quality. Combustion air from outside directly connected to equipment helps reduce spillage and uncontrolled combustion air from entering the home. However, using outdoor air as part of the combustion process reduces air changes in the home and may cause humidity levels to rise.

9.4.4 Increasing ventilation

If you still have too much condensation even after reducing moisture production, or if indoor air quality is poor, you will have to increase the rate of ventilation or air change.

Ventilation systems work under two main categories: balanced and unbalanced. Unbalanced is most common where exhaust fans are used and replacement air comes from air leakage. This can result in reduced house pressures and limited success in ventilating the house properly. Balanced ventilation incorporates a system where exhausted air is replaced with a dedicated source of incoming air. This helps keep house pressures close to neutral and helps to ventilate the house more evenly.

Ventilation can be increased by 

• Turning on kitchen and bathroom fans when those rooms are used. A simple timer or humidity controller will turn the bathroom fan on or off automatically to ensure proper ventilation and avoid over-ventilation.
• Installing ENERGY STAR^® certified fans. It is worth buying quieter models designed for continuous use. Noisy fans tend not to be used much because they are annoying.
• Ensuring that all fans fully exhaust to the exterior and incorporate air sealing measures in their installation. Avoid kitchen range hoods that recirculate air back into the room.
• Installing a balanced central system incorporating a heat or energy recovery ventilator (HRV or ERV) to ensure improved indoor air quality (see Figure 9-3).

A somewhat effective ventilation technique involves having a contractor install a fresh-air duct with a damper to the return-air plenum of a forced-air system (see Figure 9-5). The forced air system should be interlocked to appropriate exhaust fans to avoid pressurizing the house and pushing moisture into the building envelope. Outdoor air is drawn in by the suction of the furnace fan, mixed with house air and preheated by the furnace. Typically, the inlet should be located on the return air duct a minimum of 3 m (10 ft.) from the furnace inlet. The contractor should ensure that the cold ventilation air does not adversely affect the furnace in any way.

Open the damper in the outdoor-air duct just enough to prevent window condensation. It will have to be adjusted periodically through the seasons. Alternatively, a motorized damper with a humidistat control can open the damper only when the house becomes too humid.

Some ventilation systems are designed with a central exhaust fan with several ducts pulling air from the kitchen and bathrooms. Better yet, incorporate a heat recovery ventilator that typically recovers 70 to 80 percent of the heat from the exhaust air and transfers the heat to the incoming air. Central ventilation systems should be designed, specified and installed by a professional.

9.4.5 Heat recovery ventilators and energy recovery ventilators

An energy-efficient HRV or ERV is one of the best ways to ventilate a home and to control indoor air quality. HRVs and ERVs are connected to an existing forced-air distribution system or a dedicated ductwork system in a balanced manner. It is important for HRV or ERV supply and exhaust air flows to be balanced to maximize performance and not affect the house pressure. Look for models with electronically commutated motors (ECM) to reduce power consumption. In addition, HRVs and ERVs are often available with a range of controls including programmable units to meet homeowner’s specific needs.

An HRV saves on energy costs compared to conventional ventilation systems because it recovers heat from exhausted air. The HRV exhausts stale air and passes it through a heat exchanger. The exchanger transfers the heat to the fresh incoming air before it exhausts the stale air to the outside (see Figure 9-3 and Figure 9-4).  

Similarly to an HRV, an ERV recovers heat from exhausted air, but it also allows for the moisture to be transferred between the air streams. An ERV is recommended where cooling load is high, where the interior moisture loads are very low, or where it is operating in a very dry climate (for example, northern Canada).

During the cooling season, ERVs help control excess moisture in your home by allowing it to pass through the core. For example, in hot humid regions some of the moisture in the outdoor supply air is transferred through the core to the outgoing exhaust air. Because less energy is required to lower the temperature of dry air compared to moist air, an ERV can reduce the load on your air conditioner.

On the other hand, if the amount of moisture produced in your home is limited during the heating season, ERVs can help recover some of the moisture that would be exhausted to the outdoors by a regular HRV. This helps you maintain a humidity level within your home, minimizing static electricity, sore throats and other discomforts caused by air that is too dry. Also note that this dryness could be caused by over-ventilation, which might indicate that the ventilation system is oversized or needs to be slowed down.

HRVs and ERVs must be installed, balanced and commissioned properly by a certified technician. Historically, many HRVs and ERVs were not installed or maintained properly, so if you are unsure of how your unit is set up or performing, contact a certified professional (ideally trained for your make and model). Like all HVAC equipment, once properly set up, HRVs and ERVs must be serviced regularly. The homeowner should be able to perform routine maintenance as this typically only requires cleaning filters and the core, and checking components as noted in the service manual for the unit. Visit the Heat and energy recovery ventilators section of our website for more helpful tips.

9.4.6 Combustion air

All fuel-burning appliances require air for combustion and for diluting and exhausting the products of combustion out of the house. If the air supplied to the house is less than the amount of air exhausted, a negative pressure is created that can produce backdrafts of combustion gases (see Figure 9-6). For example, a powerful kitchen fan or a roaring open fireplace exhausts air from the house creating a negative pressure that can pull combustion gases back into the house through chimneys or vents.

Signs of combustion air problems include:

• Back-puffing of the furnace, boiler or water heater (indicated by soot or staining around the air intake, burner, barometric hood, damper or chimney connections), or melted plastic fittings on top of the tank-type water heater.
• Unusual odours or hot and muggy air around or from the combustion appliance.
• Difficulty starting or maintaining a fire in the fireplace.
• Occupants experiencing frequent headaches, skin or throat irritations or nausea.
• Unexplained or nuisance smoke or carbon monoxide alarm signals.

Conventional open fireplaces can be a wonderful feature of a home, but they are also responsible for leaking heated air to the outside and are prone to backdrafting. At the end of their burn cycles, when the wood burns to coals, heat output is reduced and large quantities of carbon monoxide are emitted. At this point fireplaces are more vulnerable to backdrafting. Minimize this problem by installing tight-fitting glass doors and consider opening a nearby window slightly when you operate the fireplace or install a designated combustion air supply.

Safety warning:

Always install CO detectors in a home that has combustion appliances (fireplace, wood stove, fuel-burning furnace or water heater) or an attached garage. Properly installed, these detectors will help protect occupants from asphyxiation caused by a venting failure or malfunction of combustion appliances or automobile fumes leaking into the home from an attached garage. Never operate a vehicle in an enclosed space. Always open the garage door before starting a car inside.

Regularly replace batteries in CO and smoke detectors. These devices have limited life spans and must be replaced regularly. Check the manufacturer’s literature for this information.

9.5 More ways to save energy

Explore the Energy efficiency renovations section of our website to access a wealth of additional tips on saving energy in your home and to learn more about how an EnerGuide home evaluation can help you make informed decisions when operating, renovating or purchasing a home.