What Are the Steps You Can Take Toward Making Your Home Net Zero Energy?  

I don’t know anyone who doesn’t like the idea of saving money, which will happen when you convert your home to “net zero energy.” So, what are the steps you can take to get there?

Net zero energy” means that your home generates more energy than it consumes. With “net metering,” your electric meter runs backwards when your solar panels generate more electricity than you’re using (on a sunny day), then runs forward at night, resulting in zero (or less) net consumption of electric power.

Solar power gets more affordable every year. When I purchased my first 10-kW solar photovoltaic system 15 years ago, the cost was over $60,000, but Xcel Energy gave a rebate of $4.50 per watt, so I got a check for $45,000 from the utility, reducing my net cost to $15,000. Nowadays that same system would cost as little as $15,000 with no Xcel rebate but a 26% federal tax credit.

While you can generate your own electricity, you cannot generate your own natural gas, so terminating natural gas service is key to achieving net zero energy. This involves some major system changes if you are currently heating your home and your water using natural gas, cooking with gas (including with a gas grill) and have a gas fireplace.

There are electric alternatives to all of these uses of natural gas, and you’ll appreciate that eliminating natural gas also eliminates the possibility of a gas explosion and of carbon monoxide poisoning (unless you have a gas powered car).

Heating your home with electricity used to mean installing baseboard resistance heating units in each room, but that is so 20th century. Nowadays electric space heating is done far more efficiently (and evenly) using heat pumps.

Gas forced air furnaces and water heaters are considered to have a 15-year life expectancy, so when yours fail, think of that as an opportunity to adopt heat pump technology for both functions. And a heat pump eliminates the need for a separate A/C unit, since it heats and cools.

Gas furnaces and water heaters generate heat by burning gas. A heat pump moves heat, similar to what A/C does. (How heat pumps work) It cools your home by moving the heat out of your house. If you put your hand over the external compressor unit while it’s cooling your home, you will feel the heat that was moved from inside your home. In heating mode, the process is reversed, and the heat pump moves heat from outdoors into your house. It may surprise you to know that when it’s freezing outside there is actually heat that can be moved from outside to the interior of your house, but it’s true. (Heat pumps work in extremely cold climates) Our office has been heated solely by heat pump since November 2017, and ever since there has never been a day when the system failed to keep our office at 70°F or warmer.

A simple one-unit 12,000-BTU, 29.3-SEER ductless mini-split system from Fujitsu can be found online for $1,961. That’s a small unit, suitable for one room or a garage (a great application!). For our office, we bought a Mitsubishi system in which a single compressor drives three separate wall units, each with its own thermostat.

A heat pump water heater (which I installed at our home) has the compressor built into the unit, above the tank. You can feel cool air emitting from it when it is heating water. I suggest putting it in a wine cellar where it’ll keep the room cool without buying a separate A/C unit.

For cooking, you’ll be amazed and delighted by the induction cooktops that are now widely available. I saw them used on a cruise ship for both cooking and warming surfaces, and the chefs loved them. (Modern cruise ships have eliminated natural gas because of the fire hazard.)

An all-electric home will, of course, demand more electricity, but Xcel Energy now allows you to install enough solar panels to generate double your electrical usage over the prior 12 months. That is more than enough to cover your new electric space heating, water heating and cooking needs, with capacity left over to charge an EV, too.

An important first step in pursuing net zero energy for your home is to reduce your need for energy, and the easiest and cheapest way to do that is to improve your home’s insulation. I had Dennis Brachfield of About Saving Heat blow cellulose insulation into the exterior walls (not just the attic) of a 1940s bungalow I owned, and I was astonished at how much more comfortable the house became. Even if your exterior walls have batt insulation in them, there is still space in the walls to blow in cellulose. (How to insulate an old house)

I learned something interesting from that experience. We all know that walls can radiate heat, such as a brick wall in bright sunlight. Well, walls can also radiate coldness, or suck heat. The air temperature in my bungalow before and after blowing in insulation was the same, but I felt warmer and burned less gas.

You can go beyond improving the insulation of your exterior walls and attic. There are numerous places that allow cold into your home, especially around your windows. Whether or not you install triple-pane Alpen windows, as we did at our office, caulking around the window frames and elsewhere can reduce the energy needed to heat your home.

A blower door test done by a contractor will identify the air leaks in your home. Insulating your attic with blown-in cellulose and your crawlspace with plastic sheeting will also reduce your home’s energy needs whether from gas heating or your new heat pump. (Insulating crawl spaces)

Of course, many homes, especially in older neighborhoods, can’t benefit from solar power because of shading from trees or insufficient south-facing roof area, but you can purchase community solar. (This is also a good solution for condos which have no roof at all.)

The way community solar works is that you invest in solar panels that are part of a solar farm in some distant pasture. The electricity generated by your panels in that remote location is credited to the electric meter for your home or condo. One advantage of community solar is that when you move, you only need to change which meter gets credited with your solar production.

Other ways of reducing energy use include replacing CFL or incandescent light bulbs with affordable LED bulbs and “daylighting” your home or office. (Batteries + Bulbs sell 8-packs of 60W LED replacement bulbs for $6.49, tax included, after $15 instant rebate.) We have “sun tunnels” in our home and office to bring daylight into interior spaces. In fact, on a sunny day we don’t need to turn on any lights in our office. It’s great— and saves energy. We had Design Skylights of Evergreen install Velux sun tunnels at both home and office.

Would you like one of us to visit your home for a private consultation about the sustainability possibilities in your home? Email me at Jim@GoldenRealEstate.com.

Sustainability Series Session #1: The Many Facets of Insulating a Home

This Thursday, January 17th, is the first of Golden Real Estate’s 6-part Sustainability Series. The topic this week is home insulation. Allow me to introduce the presenters and to share some of what I myself have learned from insulating my own homes and office, and from 17 years of selling homes and being active in the sustainability arena.

We have two great presenters at this month’s session. One is Steve Stevens, whose passion since retiring from Bell Labs has been the conversion of an energy-wasting 1970s brick ranch into a showpiece of sustainability through solar power, energy efficiency and super insulation. In addition to having insulation blown into his attic and walls, he had layers of poly-iso and structural insulated panels added to his exterior walls.  Then he went so far as to dig out and expose his home’s foundation walls so poly-iso insulation could be applied to them. He also constructed “air locks” on all entrances, and built a greenhouse on his south-facing exposure — both extremely effective insulating techniques.

Several years ago when Steve’s home was on the Golden Solar Tour, I shot a 40-minute video in which Steve described his home’s sustainability features — by far the longest of all the videos I have ever created for homes on that annual tour. A link to the video is at JimSmithColumns.com

The other presenter is Dennis Brachfield of About Saving Heat. I’ve known Dennis for over 25 years. His company insulated an office building I owned in Denver as well as a couple homes I have owned.  Dennis is bringing a blower door to this evening’s session in order to demonstrate its function. Using a fan to depressurize a home, a blower door helps to identify the location and extent of air leaks in a building.  Another tool Dennis will illustrate is an infrared camera. By pointing it toward ceilings and exterior walls, the camera shows the difference in surface temperatures, indicating areas that could benefit from air sealing and/or additional insulation. 

I’ll never forget the time 15 years ago when Dennis blew insulation into the exterior walls of a 1945 wood-frame bungalow I had purchased. The home’s gas forced-air furnace kept the ambient temperature at 70 degrees easily enough, but occupants still felt cold.  Dennis pointed out that even if there was insulation in the walls, voids surely existed, due to a combination of sub-par installation and years of settling. I was amazed at how much more comfortable the house was after having insulation blown in to fill all those voids. What I learned from that experience was that cold walls radiate coldness just as effectively as warm walls radiate warmth. Thus, a room with 70-degree air but cold walls feels cold in comparison to a room with the same air temperature but with walls that aren’t cold.

My current home was super-insulated by Bill Lucas-Brown of GB3 Energy.  I invited Bill to join us tonight, but he had a previous commitment. On www.GB3Energy.com, you can watch a Golden Solar Tour video I shot in which Bill describes his weatherization work, which included insulating the crawl space and the rim joist area. It’s very informative.

Here’s a simple way to determine how well insulated your home is.  When you go to bed on a cold winter night and turn your thermostat down — let’s say from 71 to 67 — look to see how quickly the home cools to that lower setting, triggering the furnace.  If it’s less than a couple of hours, you could probably benefit from improved insulation of your home. I’ve started turning our thermostat down an hour or more before bedtime and I’ve found that the temperature doesn’t drop enough to trigger the furnace until 3 a.m. or later.

When your home is that “tight” it’s important to ensure the introduction of enough fresh air to maintain good indoor air quality. For that, consider installing an “energy recovery ventilator,” or ERV. This device replaces a standard vent fan with a heat exchanger that warms incoming fresh air by extracting heat from the interior air that is being exhausted.

The ERV’s function will be explained in our session — or you can Google “energy recovery ventilation.”