Even though your furnace has probably already kicked on several times this season, it’s never too late to think about how to reduce the cost of heating your home. Since most readers have gas forced air furnaces, as do I, I’ll write from that perspective.
Actually, I have a hybrid forced air furnace, which combines an air source heat pump with a gas furnace. In the summer time, the heat pump functions like your typical central A/C unit, with a compressor mounted outside sending chilled liquid to a chiller unit mounted above the furnace’s heat exchanger. The same fan that pushes air across that heat exchanger in the winter pushes air past the heat exchanger and through a chiller unit, producing the cold air that is distributed throughout your home, by way of floor (or ceiling) vents.
Heat pumps reverse that process in heating mode, and that “chiller” becomes hot using heat that is extracted from the outside air. That works fine unless it gets really cold outside, at which point the heat pump goes dormant and the gas furnace comes on. Since most of our winter days are above freezing and we turn down our thermostat when we go to bed, the gas furnace is largely unused, which reduces gas consumption significantly.
Natural gas heat is less expensive than typical baseboard electric heating, but more expensive than heating with an electric heat pump. Moreover, if you have enough solar PV panels on your home, you can run your heat pump without having to pay the utility company for the electricity. That’s my situation — I have enough solar panels to power my home, heat my home, and charge my cars. My gas bill is under $50 per month even in the coldest months, and much of that is for heating water, not running the gas furnace. As soon as my 15-year-old water heater dies, I plan to replace it with a heat pump water heater using electricity from my solar panels. Since a heat pump water heater chills the air around it as it heats the water within, I’m going to put my freezer in the same room so less electricity will be required to keep my food frozen.
Recently I wrote about mini-splits, a funny name for a heat pump system common in Europe and Asia, and that is becoming more common here in the United States. Being a heat pump, a mini-split operates only on electricity and is highly efficient. Also, a mini-split’s heat mode can operate in temperatures far below the capabilities of heat pumps like the one in my home. Just this week I ordered a 3-head mini-split system to replace the roof-mounted furnace and A/C unit at the office of Golden Real Estate. Since we use gas only for heating, I’ll be able to tell Xcel Energy to discontinue gas service to my building, which costs about $50 per month -- even when zero gas is consumed. You read that right: we currently pay the utility company $600 per year just for the privilege of being connected to their natural gas grid.
So much for appliances. The highest return on investment when it comes to reducing your energy costs comes from improving your home’s insulation. I recommend getting an energy audit, which uses a “blower door test” to identify the places where your home is losing heat.
If you Google “how does a blower door test work?” you’ll learn the following: A fan is installed which sucks air out of your house. The technician conducting the audit then goes through the house looking to see where air is entering the house. Those same places are where heat is leaving your house.
Our smartphone app lists two vendors who perform energy audits. You can download the app for free from the App Store or Google Play by searching “Golden Real Estate.” Or go to www.clientlinkt.com/install/243 to download it: .
There are four areas of interest when insulating your home: the exterior walls and attic (using blown-in cellulose) and caulking or sealing around windows and along the rim joist in your basement or crawl space. The rim joist is where the joists for your first floor rest on your home’s foundation. Home builders typically stuff loose fiberglass between those joists, but they don’t cover and seal that fiberglass with plastic. Cold air flows easily through that loose fiberglass “insulation.”
The company that did the insulation work in my own home is GB3 Energy, which has a video I created on its web page (www.GB3Energy.com) detailing the improvements they performed. (In that video, I also show and explain my home’s heat pump system.)
In the 1990s, I owned a 1950s bungalow with minimal insulation in its exterior walls. I hired a vendor to blow cellulose into those exterior walls, and the result surprised me. What it made me realize was that walls radiate their temperature to occupants of that room. The indoor air temperature may be 70 degrees, but if the surface of the walls is cold, you will feel colder than you would in a room with 70-degree air temperature and walls that are not cold. After the insulation was blown into the walls, the bungalow was noticeably more comfortable and my gas bill was reduced.
Whatever the age of your home, if it has the typical fiberglass insulation in its exterior walls, that insulation has probably settled and has left void areas (without insulation) in your walls. If you have a vendor like GB3 Energy blow cellulose into your exterior walls to fill those void areas, your home will feel warmer and your heating costs will go down.
When it comes to improving your gas furnace’s efficiency and reducing your gas bill, don’t neglect replacing your furnace filter at least twice per season.
You probably turn down your thermostat when you go on vacation, but do you also turn the setting on your gas water heater to “Vacation” — or turn it off completely? Doing so can also save on your gas bill.
There are so many other ways that you can improve the “performance” of your home. If you went on the Metro Denver Green Homes Tour on October 7th, you learned several. I recommend ordering a home energy audit — it’s roughly a $200 investment — and learning from it what improvements are likely to have the most positive impact and make the most sense for your home. Also, the technician performing the energy audit can be a fount of knowledge on the subject of energy efficiency, so don’t just read their report, chat with them and you’ll probably learn a lot that you don’t already know.