Electrify your home? A guide for solar homeowners

All-electric homes are fast becoming one of the latest home trends. If you want to have cleaner indoor air, the latest technology, or save money (and who doesn’t?), an all-electric home might be right for you too.

It also makes a lot of sense if you have solar panels, or you’re thinking about it. If you can generate enough electricity from rooftop solar panels, you can power all of the appliances in your home and still have a monthly electric bill that’s near zero.

And if you can eliminate your need for natural gas entirely, you can actually discontinue your service, potentially eliminating fixed monthly charges from your gas company.

You don’t need to go entirely all-electric either. If you have existing gas appliances, you might consider replacing them with electric alternatives as they reach their end of life. Replacing just one or two can have a big reduction on your gas bill.

Still, going all-electric doesn’t make sense for everyone. For example, I have a heat pump in my home, but I still have a lot of gas appliances and don’t plan to replace them anytime soon. However, if you’ve got some older appliances or you’re planning a new home, this guide will walk you through what’s involved in converting some or all of your home to electricity.

Why eliminate gas appliances in your home?

There’s a lot of reasons why you might want to go all-electric.

Electricity is better for the planet.

If you’re motivated by climate change, electricity is a cleaner choice than natural gas. Methane accounts for about 20% of global greenhouse gas emissions, and a new instrument on the ISS suggests that there’s far more methane being released into the atmosphere than previously thought.

But using methane in the home means burning it and converting it to less potent carbon dioxide, you might point out. While that’s true, most fugitive emissions come from the oil and gas industry. This means that every CCF of gas you use in your home is also linked to natural gas leaks somewhere up the supply chain.

Electric appliances are better for indoor air quality and your health.

Burning gas in your home is certainly cleaner than burning coal, which used to be commonplace in American homes at one time. But there’s more and more evidence that the emissions from your gas appliances - especially your stove - can be releasing pollutants such as benzene, toluene, ethylbenzene, xylene, and hexane.

One meta-study suggests there’s a strong link between gas cooking and childhood asthma.

You can save money.

If you’re currently heating your home with electric resistance heating - which includes electric baseboard heaters, space heaters, and electric furnaces - it’s almost a no-brainer. An electric heat pump will be 2-3 times more efficient and save you money on your monthly bills.

You can take advantage of rebates.

Many utility companies offer rebates for energy efficient appliances. Government rebates are available too, and the easiest way to find them is to visit energystar.gov.

One notable recent development is that the recent Inflation Reduction Act upped the incentive not only for solar, but added rebates for other energy-saving measures such as heat pumps. The details are still being finalized but the benefit for consumers could be large: low-income households could be eligible for a $8,000 rebate, while higher-income households can still receive $2,000 back.

Electricity is safer than gas.

Burning gas in your home causes indoor air pollution, which is discussed further in the section on stoves below. But there’s also a risk of gas leaks. While rare, leaking gas in a home can go undetected. In extreme cases, this can lead to property damage or even gas explosions that can completely destroy a property or cause loss of life.

How do you electrify your home?

As mentioned earlier, you don’t have to go all-in and replace every gas appliance in your home. The return on investment will vary, but here’s a list of the appliances you can convert to electric, from appoximate best return to worst.

Heat pumps for heating and cooling

Heat pumps can be used to heat or cool your home. In cooling mode, they work the same as a central air conditioner, taking heat from inside your house and dumping it outside. To heat your home, they reverse the process and take heat from outside and blow it inside. You might be surprised that this works even in the winter when the air is cold, but a freezer works the same way: even when the inside of your deep freezer is cold, there’s enough heat energy to heat the coils at back of the appliance.

There are two types of heat pumps: air source and ground source. Ground source heat pumps use coils that are sunk into the ground, and extract heat energy from the soil. This type is more efficient because the temperature of the ground doesn’t change much from summer to winter. The downside is a significantly higher cost due to the engineering involved.

Air source heat pumps are much more common, and look like air conditioners. This article won’t get too much into the details because I’ve written one already on heating your home with solar power.

Should you upgrade? If you heat with electric resistance heating, you will save money by switching to a heat pump. An air-source heat pump will approximately be twice as efficient, cutting your heating bills in half. A ground-source unit will be even better and result in a heating bill that might be just one-third.

If you’ve got a gas furnace, the financial advantage is a little less clear. Gas prices have been particularly volatile recently and are expected to be especially high in winter 2022-23. However, electricity prices will rise for many too. This means that it might only make sense to switch from a gas furnace to a heat pump if you can zero out that additional electric usage with solar panels.

Calculating this means understanding how much you need to expand your solar array to generate the annual electricity consumed by your heat pump, and comparing the cost of that system expansion to your gas bills from heating your home (plus a small amount of electricity used by the furance fan).

Electric oven and stove

Electric stovetops and ovens have been around for a long time, so using electricity instead of gas for cooking isn’t new.

However, what is new is the growing popularity of electric induction cooking. Conventional electric stoves are based on electric resistance: think of how hot an old-school light bulb gets. Non-induction electric stoves work on the same principle.

Induction cooking, on the other hand, works by using an oscillating magnetic field to heat metal cookware directly. This has a number of advantages:

• It’s more efficient. According to a study by Lawrence Berkeley National Laboratory, electric induction cooking is 84% efficient, while electric coils are only 71% efficient. Meanwhile, gas stoves are much worse: only 40% of the heat from the flame of a gas stove is captured by the cookware.
• Instant heat. Electric induction heats instantly, much like a gas stove.
• Faster heating. Because of the high efficiency, electric induction transfers a lot of energy into cookware very quickly. Because of this, induction will boil a pot of water significantly faster than any residential-class gas stovetop.
• It’s safer. With electric induction, the surface of the cooktop will only get warm due to contact with hot cookware. It doesn’t heat the cookware directly. There are also no hazards like the risk of leaving an unlit gas burner on, causing natural gas to accumulate in your home.

One notable development is that electric induction ranges (which combine an induction stove with an electric oven) are significantly cheaper than they were just a few years ago. They now start at about the same price as a mid-range gas model. Electric ranges are still about half the price of induction, but these tend to be aimed at the lower end of the market and have fewer features.

To power one of these, you’ll need a 40 amp or 50 amp 240 volt outlet.

Electric hot water

Just like heat pumps can be used for heating your home, they can also be used to supply a home’s hot water needs. A heat pump hot water tank combines a heat pump with a hot water storage tank. Here’s what one looks like:

It looks like a normal hot water tank, but the top of the unit contains a small heat pump that pulls in surrounding air, extracts heat from it, and exhausts cold air back out. This one is a hybrid model because it contains an electric resistance coil for backup heating in situations where the heat pump can’t supply enough energy.

Sounds great, but the downside is high cost. The cheapest 50 gallon heat pump hot water heater I could find on Home Depot is selling for $1,700. In comparison, the cheapest 50 gallon tanks I could find that use electric resistance heating costs $519, and $669 for a 50 gallon gas-powered tank.

Will you save money by going with a more expensive heat pump unit? Manufacturers publish the wattage of their tanks, but unless you know how many hours your tank will run to keep up with your hot water usage, that won’t help much. The easiest way to figure this out is to look at the EnergyGuide label.

The numbers on this label are based on test standards set by the federal government, which will allow you to make a fair comparison between products. Here’s an example of a label for a heat pump hot water tank:

There are three key things to look for:

• The estimated annual energy cost
• How much hot water the tank will generate in the first hour that its on
• The estimated annual electricity usage

By looking at the label for equivalent capacity tanks, you can use the estimated annual cost to decide if a gas tank, electric resistance tank, or heat pump tank would be better for you.

The upfront cost of a heat pump tanks is twice or three times that of other types, but are much more efficient and may save you money in the long run. For example, the EnergyGuide label above is for a 50 gallon Rheem heat pump tank and estimates that you would spend $104 per year in electricity. Meanwhile, the label for a Rheem electric resistance tank with equivalent capacity estimates the annual cost as $419. That’s a $315 difference. Based on the price I found on a big box store website, the heat pump version would pay for itself after less than 4 years.

With the help of the EnergyGuide label, you can do this comparison yourself with any models that you’re considering. Here’s an example:

Given that you should expect a hot water tank to last at least 10 years, a heat pump version will save you money versus both conventional electric and gas. However, a big caveat is that the EnergyGuide label is based on national averages for electricity and gas prices, so you if you know what your local prices are, you can do your own more accurate calculations based on the yearly usage indicated on the label (highlighted in red above).

The last caveat is that your personal usage will vary, so if you think you might use more or less hot water than the average household, you can adjust these numbers up or down based on your personal estimate.

One caveat about heat pump hot water tanks

For heating your home, a heat pump will extract heat either from the air or the ground outside. However, a heat pump hot water tank will extract that heat from inside your home.

This means that if your hot water tank is sitting in conditioned space, like a heated basement, it will be “stealing” heat from the air. The effect of this is negative during the winter months, because it means your furnace will need to work to replace that “stolen” heat.

However, this is a benefit during the summer, because the water tank will cool the room by dumping that heat energy from the air into your hot water.

For many people all this more-or-less balances itself out over the year, but it might be something to keep in mind if your heating months are a lot longer than your cooling months.

Drying your clothes without gas

The best way to dry your clothes without electricity is a good old fashioned clothesline. Not only is it free, but your clothes will last longer and smell better too. I can attest to that: helping to hang the clothes was one of the chores I did as a kid.

Not everybody is able or wants to do that, though. If you want to replace your gas clothes dryer with an electric model, you have three choices:

• Electric dryer. This type uses a resistance coil and is the cheapest type.
• Heat pump dryer. A heat pump supplies the heating instead of a coil.
• Condensing/ventless dryer. This type uses heat from either an electric resistance heater or a heat pump, but also incorporates a condensor that dehumifies the air (by cooling the air, causing moisture to condense out). This has the added benefit that a drain is optional, allowing you to place the unit anywhere. However, you’ll need to empty a water tank periodically.

For clothes dryers, the pros and cons of a heat pump are similar to that of a hot water tank. You’ll pay more upfront, but will consume less electricity. Again, you’ll want to compare the EnergyGuide product labels to help you decide if it’s worth it.

Tax credits for heat pumps

As mentioned earlier, the best website to find rebates for energy efficient appliances is energystar.gov.

Previously, heat pumps for home heating were eligible for a $300 federal tax credit, but the recent Inflation Reduction Act increased the incentive significantly. We’re still waiting for exact details, but the White House published the following:

Households will be able to claim a tax credit for 30% of the costs of buying and installing a heat pump, up to $2,000 including support for any electric system upgrades needed to make the home heat-pump-ready.

Beginning in 2023 state programs will offer low- and moderate-income households rebates for heat pumps at the point-of-sale, cutting costs of purchase and installation up to $8,000. If home electrical upgrades are needed to integrate new heat pumps, rebates of up to $4,000 will also be available to households.

The current $300 federal tax credit requires that the heat pump have at least a 15 seer rating. It’s not yet known if the IRA will change the efficiency rating needed to qualify.

How many solar panels for an all-electric home?

Going all-electric means that you would need a lot more solar panels to power your home. Fortunately, solar panel efficiency has continued to get better, and today you can get ones that are as high as 22.8% efficient and generate 400 watts or more.

Being able to generate a lot of solar electricity in less space makes it more feasible to go net zero: this means that your home generates as much power as it consumes over a year. Net zero homes can look perfectly ordinary or have unusual and stunning architecture.

Even if you don’t go all the way to net zero, it can be a big benefit to upgrade just one or two appliances. How many additional solar panels will you need to electrify your home? In the case of appliances like a hot water tank, the EnergyGuide label will give you a good estimate. Heating and cooling is more complicated though. For that, you will need an HVAC professional to do an energy analysis of your home and estimate the run time and energy consumption of your heat pump.

Once you have that, you can use our solar calculator to do a quick estimate or contact a solar installer for a more accurate analysis of how many solar panels you would need to power your all-electric home.