Holy smoke! Here’s how to keep indoor air healthy and cool.

The heat just keeps on coming this summer – and now it’s served with a side helping of wildfire smoke. For many of us, that poses an extra challenge of maintaining indoor air quality while trying to keep our homes cool.

Here are some tips for coping, starting with air-quality measures and then moving through the most cost-effective ways to keep cool.

Keep the smoke out

Smoke is a serious hazard that can have long-term consequences for your health, so it’s wise to take steps to minimize it in the home.

“There’s no easy solution for dealing with wildfire smoke impacting your indoor air quality,” says Tony Haschke of Glenwood Springs engineering firm SGM. “You primarily need to stop outside air from getting in.”

Here are Hashke’s recommendations:

  • Keep windows and doors closed when the air is smoky. But open them up to bring in fresh air whenever the smoke clears, even if only temporarily – it’s very important to let clean outside air in at least once a day.
  • If you have a central air system with a fresh air intake, set it to recirculate mode or close the outdoor intake damper. When the smoke clears temporarily, open the fresh air intake back up.
  • If you have a window air conditioner, close the outdoor air damper and set it to recirculate and energy saver mode. If you can’t close the damper, don’t use the unit. Make sure that the seal between the air conditioner and the window is as tight as possible.
  • If you have a portable air conditioner with a single hose (typically vented out of a window), don’t use it in smoky conditions. If there are two hoses, make sure that the seal between the window vent kit and the window is as tight as possible.
  • Even with your AC system set to recirculate air, it’s important to have a good filter on it. The higher the MERV or HEPA rating the better – but check with your HVAC contractor to make sure your system can handle a high-efficiency filter. (You don’t want to burn out your motors.)
  • A swamp cooler requires air from the outside to operate, and has limited air-filtering capabilities. If you must run one, make sure the pads are saturated (run the pump for a few minutes before starting the fan), and run the fan on low. You can change out the water and add evaporative cooling treatment to help refresh the unit from smoke smells.
  • If smoke is getting in, or for an extra measure of protection, it’s worth investing in a portable air cleaner with a high-quality filter. A unit like this will cost at least $200; avoid cheap air cleaners as they tend to put other chemicals into the air.

Haschke, who lives in Battlement Mesa, notes that his family is finding the most relief from setting the window AC unit in their master bedroom to recirculate while running a high-quality portable air cleaner. But, he says, “everyone’s home is different and there’s not a single solution for every home.”

Keep the heat out with insulation and air sealing

We usually think of insulation to conserve heat in the winter, but insulation combined with air sealing will also keep your home cooler in the summer – and it will help keep smoke out.

Air sealing will stop the direct-air leaks into your home. Caulk and spray foam will seal up cracks and gaps in the structure, while weatherstripping will make windows and doors close tightly. These measures will also improve your home’s durability, and create a healthier indoor environment.

Insulation applied in the attic, walls and along basement or crawl space walls reduces the flow of heat through your home’s exterior. In winter, insulation keeps the heat inside. In summer, it keeps the heat out.

Air sealing can be a do-it-yourself project, or you can hire an insulation contractor to seal up the cracks prior to adding insulation. You can also install insulation yourself, but it’s typically a gnarlier job. A further advantage to hiring an insulation contractor is that they’ll use special tools to detect where the insulation is most needed.

(Talk to one of our energy coaches about rebates on air sealing, insulation and other projects highlighted in this article.)

Bring cool air in with ventilation fans

Ventilation fans are an affordable and energy-efficient way to move air inside your home and bring in cool outside air. Today’s fan technology can deliver a lot of cooling while adding just pennies per day to your electric bill.

Ceiling fans and oscillating tabletop fans move air within a room, creating a wind chill effect that makes people and pets feel more comfortable. Fans work because moving air feels cooler, but they don’t actually reduce indoor temperatures. (There’s no use in running a fan in a room that’s not occupied.)

Whole-house fans pull cool nighttime air in through open windows and exhaust the day’s hot, stuffy air out through vents in the attic or roof. In much of western Colorado, where nighttime temps fall below 70 degrees, a whole-house fan operating in a well-insulated home can meet cooling needs even on the hottest days. (However, you shouldn’t run it when there’s lots of smoke outside.)

A manual or automated switch turns the fan on after the outdoor temperature drops below the indoor temperature. The fan runs until the house is cooled down to a comfortable temperature. The cooler air will also cool down the walls, floors and furniture to help your house stay cool the next day.

Installing a whole-house fan is tricky and should be done by an experienced professional. These large fans require dedicated circuit wiring, and your house may also need additional attic vents. (One or two window fans might serve as a low-cost alternative. Or, if you’re thinking of installing a swamp cooler – see below – that can do double duty as a whole-house fan.)

It's also essential to caulk all penetrations between the attic and living space, such as attic hatches, exposed beams and recessed lights. A whole-house fan creates a positive pressure in the attic, so it’s important that air from the attic isn’t forced back into the living space through cracks and gaps.

Whole-house fans can be noisy, especially if improperly installed. In general, a large-capacity fan running at low speed makes less noise than a small fan operating at high speed. Two-speed fans give you the option of a high-speed replacement of cool, outdoor air or a slow-speed ventilation to run through the night.

Reduce heat with efficient lighting

If you haven’t replaced your old-school incandescent light bulbs with LED lights, do it now to reduce excess heat in your home. Those old bulbs waste 90% of their energy as heat!

LEDs generate a fraction of the heat, and use about a quarter of the energy compared to incandescents. They can be on for hours and never get hot to the touch. They also last far longer and cost far less to use.

LEDs are so superior, and they’re now so cheap, that it’s worth installing them in place of compact fluorescent lamps (CFLs), too.

Upgrade your cooling system

If you’ve addressed air sealing, insulation, ventilation and lighting and your home is still uncomfortably hot, then it’s time to look for an energy-efficient cooling system. The options available today are much more efficient even than those sold 10 years ago, delivering a lot more cooling for fewer dollars.

Evaporative cooling is the most affordable and energy-efficient option. While it isn't the best system for right now, given its limited ability to filter smoke, it will save you lots of money over the long term.

Evaporative cooling systems – commonly known as swamp coolers – use the cooling power of water evaporation to drop the temperature of air by 15 to 40 degrees. Evaporative cooling is very effective in Colorado’s dry climate.

Swamp coolers use less than one-third the energy of air conditioners, and cost about half as much to install. Plus, they’re quieter, and they use no refrigerants that harm the ozone layer.

Unlike central air conditioning systems that recirculate the same air, evaporative coolers provide a steady stream of fresh air into the house. They can be mounted on the roof, but many experts prefer ground-mounted units because they're easier to reach for maintenance. They can deliver cooled air directly into a central living area, or can be connected to the ductwork in larger homes. A small cooler can also be installed in a window to cool a single room.

If for some reason your home requires air conditioning, upgrading to a high-efficiency model will reduce energy costs and increase home comfort. Even if your air conditioner is only 10 years old, you may save 20-40% on cooling energy costs by replacing it with a newer, more efficient model. The more efficient models also tend to qualify for utility rebates, which lower your cost further.

Proper sizing, unit location, functioning ductwork and expert installation are all key for air conditioning units to achieve high energy efficiency while delivering cooling comfort.

Air conditioning units come in three varieties.

Ductless “mini-split” heat pumps are the most efficient, are cheaper to install than ducted central air, and can also deliver heating in winter. They use an outside compressor to feed cool air to one or more indoor air-handling units that can be zone-controlled.

According to the American Council for an Energy-Efficient Economy, you should consider buying a heat pump that has a seasonal cooling efficiency of at least 15 SEER and a heating efficiency of 8.5 HSPF. However, in colder climates (i.e., at higher elevations in Colorado) you’ll need a higher HSPF. They higher the numbers, the lower your energy costs will be in the coming years.

Central air conditioning uses the ductwork inside the house to deliver cool air from a compressor unit located outdoors. Many older systems have SEER ratings of 6 or less. The minimum SEER allowed today is 13.

Room or window air conditioners cool single rooms. They’re less expensive to install and operate than central air. Look for a unit with an energy efficiency rating (EER) of 10 or higher, and run it on energy-saver mode.