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Energy: heating, cooling and ventilation

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All elements of your home are connected – directly or indirectly. They work together as a system and efficiencies in one area may have a big impact on choices you make in another area. For example, if you are thinking about putting in a new heating system, consider first talking to a home performance professionalDownload PDF 400 K about options for improving your existing distribution system by sealing ducts, insulating your walls or attic, or air sealing your house to maximize your home’s performance first. These measures may impact the size and cost effectiveness of the heating system you choose. An estimated 40 percent of home energy use is for space heating. If your system is inefficient, as much as 30-50 percent of this energy is wasted. See tips below to improve your home’s system.

The ”house as a system” approach

  • Hire a Building Performance Institute (BPI) certified inspectorDownload PDF 400 K to conduct a blower door test to identify and quantify air leakage paths, test the duct tightness, and look for other insulation, equipment, and ventilation opportunities for improvement.
  • Remove sources of pollution at their source. For example, use your bath and kitchen fans, leave footwear outside, and refrain from smoking indoors.
  • Install a whole-house ventilation system to dilute existing, small-sized pollutants, and rely on filtration to remove larger particles. Filtration systems alone will not provide good air quality.

Heating choices

Equipment type

What makes it green?

Other considerations

Ductless heat pumps

Ductless heat pumps are 2-3 times as efficient as electric resistance and also provide highly efficient cooling.

These are easy to install and do a better job distributing warm or cool air around a home than electric baseboard or electric wall heaters, thus making living areas more comfortable. These may not be applicable for all home sizes or floor plans.

Heat Pumps

Air-source and ground-source heat pumps are 2-4 times efficient as electric resistance. These are usually coupled with ducted systems and can replace a gas or oil furnace. They also provide highly-efficient cooling, which may be desirable in some homes/locations.

Ground-source heat pumps (sometimes called “geothermal”) are very efficient yet have a high first cost and are not applicable to all sites.

Gas or oil furnaces

Choose an ENERGY STAR labeled model of gas furnace.

Older oil furnaces can be retrofitted with a new burner (called a flame retention head burner) that increases efficiency by 5 to 15%.

Change your furnace air filter once a month during the heating season. Choose MERV-8 filters, preferably approved by the American Lung Association.

Install furnace in central, well-insulated mechanical closet.

Install furnaces that match the size of your ducts and vice versa.

ECM variable speed blowers are designed to deliver a constant rate of airflow through your furnace. If your duct system is undersized, the ECM fan will operate at a high speed, which may result in a shortened life of the equipment and high electricity usage.

Get an annual checkup—cleaning and inspection— for your furnace before heating season gets into full swing.


Retrofit wood stoves with catalytic converters, which significantly lower the stove’s emissions.

Change to a certified wood stove, a wood pellet stove, or a high-efficiency gas fireplace.

Install tight-fitting glass doors to increase the overall efficiency of an existing fireplace

Consider installing a fireplace device, such as a flue top damper, air vents, heat exchangers and/or a fireplace insert with a blower, which can significantly improve efficiency and heat circulation.

Safety considerations

  • Install a carbon monoxide (CO) detector for homes with any combustion devices, especially fireplaces or wood stoves, gas or oil furnaces, and especially in homes with attached garages. CO detectors warn residents when CO concentration reaches unhealthy levels. They are inexpensive and relatively easy to install. Detectors should be placed near fireplaces/furnaces, bedrooms and at least one on each level of the home. Install CO detectors on every level of the house that has a fuel-burning appliance. Because CO gas distributes evenly in air, it is best to install the detector between 5 and 6 feet high on the wall where it is most likely to be seen. Place the detector at least 6 feet away from the fuel-burning appliance.
  • Replace CO detectors every 3 to 5 years depending on the life of the sensor. Most sensors do not sound an alarm until CO levels reach well above the EPA’s limit of 9 ppm. More expensive detector models will detect lower levels of CO and help prevent the health hazards from prolonged exposure to CO.
  • Gas fireplaces and stoves should always be vented to the outside. Any humidifiers in a condensing gas stove should be disabled and the acidic condensate neutralized and drained. Whenever possible, install sealed combustion models.
  • Season dry wood for at least six months before burning. Do not store wood indoors where it will contribute to indoor humidity. Also keep wood away from the side of the house where pests will use the woodpile to hide from predators. Wood stacked next to siding encourages mold growth and accelerates siding decay.
  • From the crawl space (or basement) and attic, use fire-rated blocking, fire rated caulk and fire rated foam to seal any gaps around a masonry chimney where it penetrates the floor and ceiling.
  • Close the fireplace damper the morning after burning a fire. Continue to keep the damper closed until the next time you start a fire.

Thermostats and controls

  • Install a programmable thermostat (7-day programmable or manual). Some learning thermostats offer additional features. Always use the features of your thermostat, whichever type it is, to match your schedule.
  • Ask a certified Performance Tested Comfort System (PTCS) Heat Pump Technician to analyze your system. Proper control settings are crucial for proper heat pump performance.
  • Install thermostats on an interior wall and keep them out of direct sunlight.
  • Periodically check your thermostat to be sure it is not perpetually stuck on “fan on” mode unless the system is designed for this.


  • Check your ductwork/distribution system. Poorly insulated or unsealed ducts can transfer up to half your heat into un-heated areas of your home. Because ductwork is under pressure, small holes can leak a lot of hot air. Pay attention to detail and seal ductwork with mastic only. Duct tape is not good for sealing ducts.
  • If you find white tape on your ductwork it may contains asbestos, which presents a serious health hazard. Contact a professional remediation specialist.
  • Close or cover forced air registers and grilles. This puts strain on the furnace, shortens its life, and increases duct leakage – a costly consequence.


  • Follow the industry’s saying of “build it tight, ventilate it right.” This refers to making sure your house is well sealed, knowing when, from where, and how much outside air is being circulated in your home, and exhausting stale air to protect your health and your house’s health.
  • For homes built before 1991, upgrade to a whole house ventilation system as prescribed in the Washington State Ventilation and Indoor Air Quality Code.
  • Install a heat recovery ventilator (HRV) to recover heat from air exiting your home. These units can recover between 50-80 percent of the heat that would otherwise be lost through ventilation. Install whole house ventilation systems, as prescribed in the Washington State Ventilation and Indoor Air Quality Code, for homes without existing whole house ventilation.
  • Look for more bang for your buck – choose systems that provide multiple functions. For example, an HRV provides filtered fresh air to your home while capturing heat leaving the house. Some forced air systems incorporate fresh air directly through the air handler (furnace). Be sure your fan is set to run daily for a prescribed amount of time regardless if the system is heating or cooling.
  • Some homes utilize trickle vents in windows coupled with pre-programmed whole house fans. While this is the least preferred method for energy efficiency, you can fine tune it for optimization. Consider hiring a home performance contractorDownload PDF 400 K to inspect this system to ensure you are circulating enough fresh air.


  • Ductless “mini-split” heat pump heaters are a great alternative to houses with baseboard or electric wall heaters. Check your local utility for rebates.
  • If you choose to install a heat pump, consider ground or water source technologies, which deliver even higher efficiencies than the common air source heat pump. Ground and water source systems, however, will require a larger initial budget and more extensive site work.
  • After you have improved your insulation levels and upgraded your heating system and appliances, consider installing photovoltaic (PV) or solar panels to convert sunlight into electricity. Look for rebates to help reduce the initial costs.

Heating, cooling and ventilation resources

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