When It’s Time to Replace Your Gas Forced-Air Furnace, Consider the Alternatives

As I write this, I have just completed shooting videos of the 15 homes on this year’s Metro Denver Green Homes Tour.

The tour, currently in its 25th year, takes place on the first Saturday in October. Normally, you would register for $10 and get a book describing the homes, along with a map. Armed with that, you create a self-guided tour of the homes which interest you. You’d have to complete your tour by 4pm that day, followed by a reception and expo.

Because of the pandemic, this year’s tour will be totally virtual, which is actually better because you’ll get a link to view detailed videos of every home on the tour and not miss any of them due to time constraints. We won’t release the URL for the tour until October, but when we do you’ll be able to take your time to view all 15 — and the virtual tour is free! I’ll publish that URL in my October 1st column.

Meanwhile, let me share one particular lesson that you will learn from viewing the 15 videos: that gas forced air furnaces, no matter how efficient, are obsolete.

One thing you learn really quickly in the sustainability arena is that America is far behind other countries when it comes to energy-efficient technology. That’s because our fossil fuel costs have always been lower than in Europe and Asia, specifically Germany and Japan, where you’ll find the most innovation and product development. Just look at this chart from statista.com of electricity costs in different countries:

Germany 33 cents/kWH, Japan 22 cents/kWH, United States 13 cents/kWH

With our cheap energy, higher standard of living and higher incomes, Americans have long been able to waste money and energy with abandon. The result has been to leave it to other countries to create more energy efficient and less costly products.

Since home heating and transportation are the most energy-intensive aspects of modern life, that’s where we have seen the greatest innovation abroad. We in America continue to play catch-up and hang on to old technology. Our continued use of gas furnaces is an example of hanging on to old technology.

For a long time, I thought that higher efficiency gas forced air furnaces was the direction we should go to reduce our carbon footprint. However, after viewing the videos of highly efficient net zero energy and even energy positive/carbon negative  homes, I think you’ll agree that it is time to abandon altogether that method of heating our homes.

Carrier Hybrid Heat Pump

When Rita and I purchased our current home in 2012 and installed the maximum solar photovoltaic system allowed by Xcel Energy (10 kW), we looked into how we might heat our home using the free energy we were creating from the sun. That’s when we learned about and purchased the Carrier Hybrid Heat® system, which uses an air source heat pump paired with a gas furnace to heat our home in the winter and cool it in the summer. It looks just like a gas forced air furnace, but the gas flame only comes on when the outside air is below the temperature at which the heat pump can generate heat from outside air.

Although Carrier still sells its hybrid system, heat pump technology has advanced far enough that gas back-up is no longer needed in our region. However, since our hybrid furnace uses natural gas so seldom, we won’t replace it anytime soon.

When your gas forced air furnace needs replacing, don’t make the mistake of replacing it with a newer and better gas forced air furnace. Instead, look into the many alternative ways of heating your home, which you’ll learn about when those 15 video tours are released in October. (If you can’t wait, Google “heat pumps” and investigate the options.)

Heat pump systems (Wikipedia link) can use your existing ductwork (as in our home), or they can be ductless (like at Golden Real Estate’s office). My January 4, 2018, column (link) described the transition to the ductless system at our office.

Solar thermal (Wikipedia link), using both flat panels and evacuated tubes, is another technology, typically augmented by electric and heat pump units, which can provide heating as well as domestic hot water. A few of the homes on this year’s tour have solar thermal systems.

Geothermal heating (link to vendor), present in other homes on the tour, takes advantage of the earth’s temperature below the surface. In our latitude that subsurface temperature is about 55°F  year-round. It is extracted by running a liquid-filled loop 300 feet or so into the earth and using a heat pump to heat that 55-degree liquid for radiant floor or forced air heating, or using it at 55 degrees for cooling in the summer. That takes less energy than our air source heat pumps, which take much colder air from outside and extract heat from it in the winter, and can then cool your house (like A/C) in the summer.

The thing to remember about heat pumps is that they don’t create heat (such as from burning fossil fuels), they move heat. The difference between a traditional A/C system and a heat pump system is that a heat pump moves heat in two directions, not just one.

Blower door test during a home energy audit. Credit: Holtkamp Heating & A/C, Inc.

There is so much more to learn about efficient heating and cooling of your home. But first, to provide the highest return on investment (and lowest heating cost), you will want to improve your home’s insulation. A blower-door test (energy.gov link), conducted by an energy efficiency professional, identifies where the leaks are in your home, so they can be sealed. A heat recovery ventilator (HRV) (Wikipedia link) can then help you bring in fresh air without losing your home’s heat.  (A heat exchanger within the HRV transfers the temperature of the outgoing air to the incoming air.)

Thermal mass (Wikipedia link) can play a big role in reducing the energy needed to heat a home. You’ll see thermal mass applications in many of this year’s videos. Concrete, brick, water and even dirt can function as a thermal mass to accumulate heat from the sun and then release it slowly after dark. (There is an example of a “climate battery” (vendor link) using dirt on this year’s tour.) With the proper roof overhang on south-facing windows, your thermal mass is shaded from the sun during summer months but exposed to the sun in the winter, when the sun is lower in the sky.

The best way to heat and cool your home may be different than the best way to heat and cool someone else’s home, and it’s hard to do justice to this subject in a single article.

Here are a couple vendors I’ve used who would, I’m sure, be happy to give you some free advice about the best heating system for your home.

  1. Bill Lucas-Brown, owner, GB3 Energy – www.GB3energy.com, 970-846-4766 or bill@gb3energy.com. He sells and installs heat pump systems, but also does energy audits, including blower-door tests and will super-insulate your home as he did for my current home and for the Golden Real Estate office.
  2. Dennis Brachfield, owner, About Saving Heat – 303-378-2348 or info@aboutsavingheat.com. Dennis does blower-door tests and will super-insulate your home, based on what the test reveals. He does not sell or install heat pumps or mini-splits, but he can refer you to someone and probably give you good advice about their applicability to your home. I have known Dennis for 30 years, and he has tested and insulation several homes for me.
  3. Note: HomeAdvisors would be a reasonable choice for such a project. I have not used them, but I am impressed at their quality control regarding the vendors they work with. Did you know this national company is actually based in Golden? Originally called ServiceMagic. (888) 921-3034
  4. For geothermal heating, see the link in the paragraph about geothermal heating for a vendor who sounds great to me, but whom I haven’t used.

Buyers Benefit From Having an Agent Who Knows Home Systems and Sustainability

One of the reasons I enjoy showing homes to buyers is that I get to educate them about home systems and how they work, as well as identify the sustainable and not-so-sustainable features of each home.

The agents at Golden Real Estate have a thorough understanding of home systems as a result of our combined decades of experience and hundreds of transactions. In addition, we have taken classes on energy efficiency, insulation, solar power and home construction which allow us to serve buyers better when we show them homes.

Together, for example, we toured the model homes at Richards Farms when they were under construction, where we learned, among other things, about that builder’s foam insulation process.

There are so many aspects of energy efficiency and sustainability. Everyone by now knows about solar photovoltaics — creating electricity from the sun. Our office has 20 kW of solar panels, but having solar power is only the beginning. It’s how efficiently you use that power that makes the difference.

Heating and cooling is the biggest user of energy in any home, and the number and variety of HVAC systems have become more extensive and more complicated, and we understand and can explain them. They include: gas forced air heating and compressor-based air conditioning (most common in Colorado and much of the country), hot water baseboard heat, hot water radiant floor heating, wall-mounted heating panels or strips, heat pump mini-splits for both heating and cooling, hybrid heat-pump with gas forced air (which Rita and I have in our home), ground-source heat pump for both heating and cooling (the “gold standard” of efficient heating and cooling) — and let’s not forget heating with wood or wood pellets!

Windows can vary greatly. Double-pane windows may be standard now, but a Colorado company, Alpen, has made a name for itself with triple-pane windows and now quadruple-pane windows.  Recently I wrote about John Avenson’s Westminster home, in which some of his south-facing Alpen windows have micro-etching to divert sunlight toward the ceiling of his kitchen, a high-tech alternative to reflective window shelving, which we saw when we toured a newer building at the National Renewable Energy Laboratory.

Skylights are so 20th Century. Today’s modern replacement are sun tunnels (Solatube is a leading brand), which are great for illuminating interior rooms. Just last week I showed a home with five Solatubes in it, lighting up the living room and an interior bathroom amazingly well from the mid-day sun. My buyer didn’t realize they weren’t ceiling light fixtures until I pointed them out. (We have two sun tunnels in our home illuminating our windowless garage and laundry room, and we have four sun tunnels in the Golden Real Estate office. We don’t have to turn on any lights on sunny days!)

A knowledgeable agent can also point out passive solar features of a home, which others might not recognize. These include proper window configuration, wide overhangs above south-facing windows, thermal masses in south-facing sunrooms, and deciduous trees providing strategically positioned shade in the summer but allowing more sunlight in the winter. I like to see (and point out) cellular shades, especially vertical ones covering patio doors for cold-weather insulation.

Often I notice that the listing agent didn’t mention the features (such as the Solatubes) that my buyers and I recognize as selling points. Of course, when doing the narrated video tours of our own listings, my broker associates and I don’t miss the opportunity to point out those features. And, of course, we are sure to mention those features in the MLS listing.

Many agents miss the opportunity to write a separate description on the MLS for each individual room. It’s not a mandatory field, but it’s the best place to mention a room’s Solatube, heated floor, porcelain tile, hardwood or other feature.

The Future of Heating is Heat Pumps, Not Gas Forced Air

Here in Colorado, as in much of the country, the typical home heating system is gas forced air. A gas flame heats up a plenum across which a fan blows air through ductwork into the various rooms of a house.  For cooling, the same ductwork and fan are used, but instead of the flame heating that plenum, the air passes over a set of coils beyond the plenum with super-chilled fluid created by an outdoor compressor.

Gas forced air, however, is relatively inefficient and is only common in the United States because of our exceptionally low cost of natural gas and other fossil fuels.

Elsewhere in the world, heating is done using heat pumps. What is a heat pump? Your central air unit is a heat pump, but it operates in only one direction—extracting heat from indoor air and dissipating it outdoors. A heat pump heating system simply reverses that process, creating heat by extracting heat from outdoor air and dissipating it in your home, either through your existing ductwork or through wall-mounted “mini-split” units. Unlike gas, a heat pump moves heat instead of creating it.

How a heat pump works to heat and cool a home using wall-mounted mini-split units heated and cooled by an exterior compressor.

Rita and I replaced our gas furnace in 2012 with a hybrid system by Carrier. It heats our home using the heat pump unless the outdoor temperature falls below freezing, at which point a gas burner kicks in. With our solar panels providing the electricity for the heat pump, our highest mid-winter Xcel bill is under $50. Meanwhile, at Golden Real Estate’s office, as described in my Jan. 4, 2018, newspaper column, we got rid of our furnace and ductwork and installed a ductless mini-split system (like in the above diagram), also powered by solar panels. As a result, our Xcel bill is under $11/month year-round.

All-Electric Homes Are Practical Now, and Can Help Mitigate Climate Change

The typical American home is powered electrically but heated by natural gas, propane or other fossil fuels. You and I can generate our own electricity with solar panels, but there’s no way for us to generate natural gas or other fossil fuel energy, so the transition to a “net zero energy” lifestyle necessitates turning away from fossil fuels and going all-electric.

Fortunately, technology has advanced — just in the last decade — to the point where going all-electric is totally practical, affordable, and a way you and I can mitigate climate change

At Golden Real Estate, our office was heated with natural gas until November 2017, when we installed a heat pump “mini-split” system and had our natural gas meter removed. With 20 kilowatts of solar photovoltaic panels, we were able to eliminate our natural gas bill but not increase our electric bill. We continue to pay just $11 per month to be connected to the electric grid (which functions as our “battery” thanks to net metering), but we are generating all the electricity needed to power, heat and cool our office building. We even have enough electricity from the solar panels to power our four electric cars without buying any net electricity from Xcel Energy. We hope other businesses will follow our lead.

Making the switch to all-electric at home is still in our future, because — like you, I suspect — we prefer gas cooking, gas grilling, and having a gas fireplace.

If, however, we can get beyond those preferences, it is possible now to heat our home and domestic hot water using heat pump appliances, and to cook our food with electric or induction cooktops and ovens.  Electric grilling is also available, although not as attractive from a taste standpoint to most of us.

All-electric homes was the subject of a talk by architect Peter Ewers at last week’s meeting of the Colorado Renewable Energy Society’s Jeffco chapter.  You can view an archived video of Peter’s talk at www.cres-energy.org/video.

Once we have removed gas service from our homes (and gas cars from our garages), we will have also eliminated the risks of explosion and carbon monoxide poisoning, too.  Wouldn’t that be great?

Some Favorite Home Improvements When Purchasing a New-to-Me Home

Who doesn’t want to make some improvements on a home they have just purchased?  Here are some of my personal favorites.

Energy efficiency is very important to Rita and me, so the first thing we do is pay for an energy audit by someone like Andrew Sams of Alpine Building Performance to identify opportunities for making the home more air-tight. This would likely include blowing more insulation into walls or ceilings and caulking around windows. It might also include installing an energy recovery ventilator (ERV) to bring fresh air into the home. This device warms cold outside air in the winter and cools hot outside air in the summer by means of a heat exchanger.

I love bringing sunlight into a home, not with traditional skylights but with sun tunnels. Most people are familiar with the Solatube brand, but I prefer the Velux brand. I had Mark Lundquist of Design Skylights install a 22-inch Velux sun tunnel in my windowless garage and a 14-inch sun tunnel in my windowless laundry room — and four large Velux sun tunnels in the Golden Real Estate office. Ah, sunlight!

Speaking of sunlight, we replaced every light bulb is our house with LEDs which are “daylight” color (like sunlight), not cool white or warm white. CFLs and incandescent bulbs are so 2010!

Installing solar photovoltaic panels is a no-brainer for us, especially now that the cost has dropped so much. Your roof doesn’t have to face due south. Southeast and southwest are good enough. (That’s our situation.) Since you might be driving an electric car someday, install as much PV as Xcel Energy allows to cover that future load.  If you have just purchased an EV, Xcel will allow you to install more panels based on anticipated future use.

Don’t you hate climbing a curb to enter your driveway? Developers install those mountable curbs the entire length of the streets in new subdivisions, not knowing exactly where each driveway will be. One of the first things I would do (and have done) is to hire a concrete company to replace the mountable curb with a smooth entrance. It cost over $2,000 for our 3-car-wide driveway, but I love it every time I enter from the street! Caution: the sidewalk will now be sloped slightly and pedestrians could more easily slip on ice, so be prepared to salt your sidewalk to eliminate icing!

When your gas forced air furnace needs replacing, consider replacing it with a heat-pump furnace or mini-splits. And when your gas water heater needs replacing, I suggest buying a heat-pump water heater. The cost is about the same, and, by converting to electricity for both, you will have eliminated the most common sources of carbon monoxide poisoning in your home.

Other improvements I’d consider include: Replacing carpeting with  tile in bathrooms; and replacing regular glass with Low-E glass on south-facing windows to reduce the harmful effects of sunlight on furniture, hardwood floors and artwork.

Feb. 21st Sustainability Session Focuses on Home Heating Methods

The second  session of Golden Real Estate’s sustainability series is next Thursday, Feb. 21st, 5-6 pm, in our South Golden Road office. Some seats are still available. Reserve yours by emailing  Jim@GoldenRealEstate.com.

At this session you’ll learn about the alternative energy-saving systems for heating and cooling homes and offices including our favorite method, heat pump mini-splits.

Our lead presenter will be Bill Lucas-Brown of GB3 Energy, who installed our mini-split system.

Golden Real Estate Launches Sustainability Series

As you may already know, Golden Real Estate is a leader in sustainability, as expressed in the value statement printed on all our yard signs: “Promoting and Modeling Environmental Responsibility.” And most of our agents, including myself, are Certified EcoBrokers, having taken extra training in all aspects of sustainability as it applies to real estate.

We’d like to share what we’ve learned with you, so we’re launching a Sustainability Series that will take place on the third Thursday of every month in our office.  We can accommodate 20 or more attendees in our office, but we will move it elsewhere if the demand exceeds our capacity, so please RSVP. You can do so now for all sessions.

Each meeting will focus on a single aspect of sustainability. Here’s the schedule for the first six meetings (subject to change):

Jan. 17th — Home Insulation — Walls, windows, foundations, crawl spaces, attics. (This is a bigger topic than you might think, but it’s also the cheapest and most effective path to reducing energy consumption.)

Feb. 21st — Home Heating Methods — Forced air, heat pumps, radiant floor, solar thermal, and other technologies.

Mar. 21st — Solar Power — Rooftop and ground-mounted photovoltaic, solar gardens, solar panels vs. solar roof tiles, and home battery storage/backup.

Apr. 18th — Electric Vehicles — What’s here now and what’s coming soon in cars, trucks, motorcycles and more.

May 16th — Sustainable Renovation — What are the more sustainable and popular materials and designs?

June 20th — Water Conservation — The latest concepts and products for conserving water use, both indoors and outdoors.

All sessions are 1 hour long and begin at 5 p.m. in our Golden office or nearby if a larger space is needed based on the number of reservations received. The sessions will be led by experts in the field, although you can count on me to add my own comments!

Go ahead and reserve your seat for any or all sustainability sessions now by sending an email to  Jim@GoldenRealEstate.com. We look forward to producing this informative series!

Golden Real Estate’s Sustainable Practices

1)   Our office produces more energy than it consumes. With our 20 kW of solar panels, we heat, cool and power our office and charge our six electric cars. We also provide free EV charging to the general public, yet our Xcel Energy bill is only $11.26/month.  At our request, Xcel removed our natural gas meter.

2)   We accept polystyrene from the public in our “Styrofoam Corral,” keeping over 200 cubic yards of the material out of the landfill every year.

3)   We use only LED light fixtures and have four “sun tunnels” (skylights) for naturally lighting our office.

Click here to read about our transition to “Net Zero” in our Jan. 4, 2018, column, “Promoting & Modeling Environmental Responsibility.”