Preparing an Old House for Electrification, Part 1

Preparing An Old House For Electrification [Photo By Scottbb, Flickr.com, CC License]

With the Inflation Reduction Act providing lots of incentives to improve your home  and go all-electric, let’s look at how you can prepare for the conversion.  As with any home improvement job, it’s best to do your homework.  In this article, I’ll begin with some important questions to ask.  Then, in a followup article, I’ll walk you through some of the things you can do to make the transition to an all-electric home easier.

Questions to ask

The first thing to do is to take stock of your current situation.  Here are some questions to get you started.

1.  Does going all-electric make sense for your house?  If you just put in a brand new high-efficiency furnace two years ago, you might want to wait.  That’s a big investment to throw out.  Then there are the upfront carbon emissions that would go along with replacing it.  As much as I’d like everything to be all-electric right away, we need to do this in a smart way.  And throwing lots of upfront carbon at the problem isn’t that smart.

Another reason not to go all-electric would be having a gas tankless water heater with no good way to change to an electric storage water heater.  If you have to go from gas tankless to whole-house electric tankless, you’ll use a lot of electricity to heat water.  Worse, you may have to make a significant upgrade to your electric service because electric tankless water heaters take A LOT of power.  A better use of your resources might be to improve your hot water distribution system.

2.  Which appliances will you need to replace?  The place to start is by looking at what fuels other than electricity you use.  Gas?  Propane?  Fuel oil for heating?  If you heat with fuel oil, your home is ripe for converting to electric heating.  Gas heating is good to convert, too, unless it doesn’t make sense.  (See previous question.)  Propane is expensive, so it may be cost effective to do that conversion, too.

3.  Should you make improvements to your home’s building enclosure?  If you’re going to change the heating system, it’s a good idea to see if you need to do air sealing or add insulation.  Reducing your heating load is an excellent complement to heating with heat pumps, and there are incentives to help you do that, too.  (And speaking of heat pumps, they work in Minnesota and they work even when undersized.)

4.  Will you need to upgrade to a larger electrical service?  The electrical power delivered to a house has a limit, usually measured in terms of electrical current.  In newer homes, it’s usually 200 amps.  If the current goes higher than that, the main breaker will trip to prevent wires from overheating and your house from burning down.

Older houses that haven’t had their electrical service upgraded may have an upper limit of 100 or 150 amps.  You may still be able to work with that, but it’s going to depend on what your current electrical load is and how much you’ll be adding.  I’ll have more detail about that in part 2 of this series.

5.  Is your wiring adequate?  In addition to the electrical service, the wiring in your house may not be adequate.  At a minimum, you’ll probably need to add some new circuits.  At worst, you may need to rewire the whole house.  This is where you’ll need an electrician to help.

6.  Does your electrical panel have room for additional breakers?  Going all-electric will almost certainly mean adding new circuits.  That takes space in your electrical panel because each circuit needs a breaker.  In part 2, I’ll show you how you may have the space in your panel even if every slot already has a breaker.

7.  How much will you be able to get in incentives to help with the conversion?  The Inflation Reduction Act is only one source of financial assistance you can tap into.  There are existing federal tax incentives available, and your state and electric utility may have incentives to help you electrify your home, too.  A great resource for this is the Database of State Incentives for Renewables & Efficiency, (DSIRE).  I know Canada also has good incentives for heat pumps.

Next steps

These questions are meant to get you thinking through the logistics of doing a conversion to an all-electric home.  In my followup article, I’ll go into more detail about things you can do to prepare.  The main topics I’ll cover there are:

  1.  Plan your conversion
  2.  Monitor your power use
  3.  Map your circuits
  4.  Have an electrician evaluate your electrical system

I’m sure there are other good questions to ask as you start down the path to electrification.  Some of the reasons for electrifying are to decarbonize your home, switch to a more comfortable heating system (heat pumps), or take advantage of current incentives.  If you think of something I missed, put it in the comments below.

 

Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia. He has a doctorate in physics and is the author of a popular book on building science.  He also writes the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard.

 

Related Articles

Introduction to Whole-House Electricity Monitoring

Air Conditioner Sizing: Load Calculations vs Rules of Thumb

The #1 Reason to Have an All-Electric Home

 

Photo of electrical panel at top by scottbb from flickr.com, used under a Creative Commons license.

 

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This Post Has 27 Comments

  1. Where did you get that electrical panel picture? I have never seen one that was wired that neatly. Must have been out of a text book 😉

    1. Roy: You’re right. It is indeed rare to see a panel wired so neatly. My electrician in the house I built was a meticulous wiring fanatic, but I don’t have a good photo of that job handy. I got the one in this articl from flickr. The link is at the bottom of the article.

    2. Professionally trained with an apprenticeships! Although the ty-wraps should not be used to bundle the wires because of the over heating potential

  2. Don’t forget to check with the utility company supplying the electricity. Although they want to sell you more juice, there may be local grid issues that could delay upgrading (new transformer for your street, new wiring, etc.). Make sure you get their OK before you start to make the change and get a timeline from them if upgrades are required – utility transformers for instance are in short supply right now with lengthy wait times.

    1. Roy: Good point. For some homeowners, though, it shouldn’t be necessary. If you do an analysis of your whole-house power draws and it stays significantly below the electrical service threshold, I’d think the power company should have the street transformer sized appropriately already. One thing working to the advantage of older houses is that more efficient appliances have reduced power draws.

      1. Utilities are notorious for under sizing their transformers to residential customers. They base it on what the average consumer uses and rarely take what appliances are installed until there is an overload problem. Common to install 15KVA transformers at the street for 200A resi services. Do the math, not even close. Although today for underground services they will usually install 200A wiring to the house for any size service 200A or less service. Replacing the aluminum wire is expensive relative to just supplying the 200A wire immediately. No so for the transformer. Overhead services I’m not so sure on the wire sizing used today vs service sizes.

        1. Denny5085: I don’t know what the utility protocol is for sizing transformers, but I’m sure they would never base it on 100% of the service for all homes served. That’s never going to occur. Maybe they still do undersize, but when they do, they pay for it in blown transformers and bad customer relations. I’ve seen only one transformer blow in my 61.8 years on the planet, and that was because someone in the neighborhood invited all his friends with RVs to come to his house on Grand Isle, Louisiana and plug into the neighborhood system. I was a kid at the time and don’t know the details. I just know there was a loud pop, and then the lights went out.

      2. Agreed – most homeowners will have no need for a major upgrade and no problem. I was referring to those who may need a full upgrade from the power pole to their house, especially in older neighborhoods with original wiring.

  3. The grid will need more and more Demand Response, and a tankless water heater does not fit the bill. An electric tank water heater allows the resident to draw hot water any time and allows the grid to decide when the tank draws electricity from the grid. The tank’s storage capability is key. We need to look for more ways to decouple the time we benefit from energy from the time that the electrical energy is drawn from the grid. What are the possibilities for storage for space heating (12-24 hours)?

  4. Heat pumps are great for absorbing heat from the air but most do not provide heat when ambient temps are colder than 10-15 degrees Fahrenheit below zero, and therefore require backup resistive heating, which could easily cost more to operate when you have 30 or more days of deep cold weather below zero like Colorado has recently experienced.

    1. Randy: Anyone installing a heat pump in a cold climate should install a cold climate heat pump. Here are two articles showing that cold climate heat pumps do very well at low temperatures. The first is about Gary Nelson’s house in Minneapolis. The second is about how my heat pump performed when we got down to 7 °F in December. Neither of these heat pumps has any auxiliary heat.

      Can a Heat Pump Work in Minnesota?

      My Undersized Heat Pump in an Arctic Blast

      There are a couple of other important facts to note. First, while your location may occasionally hit -10 to -15 °F, most of your winter hours are above 0 °F. Yes, you may use auxiliary heat when it’s that cold. Second, having a really good building enclosure can keep you warm even without auxiliary heat.

      You bring up an important point, Randy. Even when you’re not in a cold climate, it’s good to have a plan for resilience so you can get through those extreme weather periods. I think the people in Texas got that message two years ago.

      Heat Pumps, Auxiliary Heat, and Resilience

      The article above discusses that issue.

      1. They should probably also consult the Northeast Energy Efficiency Partnerships website: https://neep.org/heating-electrification/ccashp-specification-product-list for heat pumps that work in cold weather.
        Also, Consumer Reports has an article from August 2022 about cold weather heat pumps with links to people that have used them down to -29F: https://www.consumerreports.org/heat-pumps/can-heat-pumps-actually-work-in-cold-climates-a4929629430/

        Allison,
        I am looking forward to this series because I have been talking about changing to a heat pump for a few years now. I have a 1974 house and I am planning on having the attic sealed this spring and will be installing R-60 insulation up there. I live in Denver and as Randy mentioned it can get cold here so I want to prep my house before that. Then get a blower door test and a Manual-J done.

    2. We have a ground source heat pump, 2 ton capacity in a fairly tight and fairly well insulated 2200 sq. ft. older home in northern Delaware. It has no problem keeping the temp at 70 when it’s 5 outside ( personal experience last December), same when it’s 100 ( like last summer). It’s a long term investment but the incentive money helps.

  5. “I feel your pain” (Bill Clinton)…
    Did my 1903 Victorian ca 2002, was still knob & tube, one outlet, one overhead light per room, a 1911 upgrade from the gas. Was VERY lucky to find electrician who was an artist. My suggestions
    1) quad outlets or more EVERYwhere. You will be glad later.
    2) Prepare for solar and battery backup to the extent possible.
    3) leave a 12″ loop of romex on every entry/exit to junction boxes, outlets. if something needs to move or be repaired, it will save the whole cost.
    4) Bigger panel than you think you need. You will need more.
    5) Test everything for grounding and power quality before signing off on the contractor. They are human too.

    1. I wired outlets that way when we put an addition on the house. Yes, it’s very convenient in those places where three or four plugs compete for space. However, I would do it differently if there’s a next time, because adaptors (similar to what I used to call octopuses) are available to plug into a dual receptacles, providing space for six plugs. Where I need more than two, I would plug in an adaptor. Wiring one dual receptacle avoids the extra jumpers needed for a quad receptacle.

  6. WHY not, or WHEN will we start wiring for USB lighting? Every light in my house is LED, and everyone has a transformer from AC to DC. That’s a tremendous waste of materials and money. Why not wire all overhead and wall lighting for USB power instead. And run USB to every outlet and do away with all those wall warts (costly unsightly, and end up in landfills).
    Single transformer for the whole house. Some will faint at the idea of going back to DC, but really, USB is everywhere in the house already.
    This should be brought up for discussion…

    1. All those converters getting warm tells you how much energy you are wasting.

    2. Thank you for you comments. When we moved to our place 15 years ago, a house built in the early 50s, we did a heavy up (old panel was 60 amps, but the service lines from the pole was only 40 … Odd) to 200 amps, and replaced the old oil furnace (which had a cracked plenum) with a heat pump. The only AC had been a 1980s vintage through wall unit. It also had an old Sears central air unit, but that had stopped working many years before. At the time there was no concept of solar, so your second point wasn’t even something we thought of, but we did put in a generator outlet / disconnect. I really like quad outlets, and have been doing them for many years, whenever possible. It has saved me many power strips and weird adapters. I don’t know why they aren’t done more, or why the electricians I have dealt with don’t like or recommend them. They are definitely more of a pain to install. Regarding your comment about USB lighting, Datacenters moved to DC power years ago. Instead of having a power supply in every chassis in the rack (so hundreds of power supplies, with the added heat and inefficiencies of each) they now have a large power supply for the needed DC, which is fed to each blade. It has saved a ton of money up front as well as in utility costs and cooling costs. I don’t know if the smaller scale of residential (or even light commercial) will ever be a market, but the idea is sound.

      1. Thanks, I was beginning to think noone liked me USB house lighting idea. I too noticed it in data centers. Now folks are retrofitting USB to outlets and power strips which is far more expensive than one transformer and wiring during installation / construction.

  7. A good first step is a whole home energy monitor installed in the electrical panel. This will provide the user with some insight into load usage and where opportunities are.

  8. How did you skip CO from back-drafting hot water tanks, hot furnace flues, the real if overblown gas stove pollutants, and natural gas leak panics? Those are all real concerns separate from decarbonization.

  9. Hi Allison, It’s been a long time but I’ve been following some of your posts. Spring of 2020 I made the plunge into electric. 43 solar panels, micro inverters (15.5K), heat pumps, hot tub and Chevy Bolt with over 20k miles a year. Last year here in Maine we produced 19.8 megawatts and used 19.7 (43 kilowatts on the plus side) System will pay for itself in about 4 years and that doesn’t include the efficiencies of the Bolt. For you engineers, you do the math. 61,000 miles in 3 years. Previous car got 25 mpg. That’s 2440 gals of gas and no oil changes either. You plug in the ave. gas price. Oh, and my ventilator runs at high speed all the time. That’s 192 cfm in a 3000 sq/ft home. Looking forward to low bills in retirement. LOL Cheers, Kurt

    1. Very nice, Kurt! I’m pursuing a similar approach here in Maryland with a somewhat challenging ~4k sq. ft. split level built in 1973. Energy audit, insulation, 400A heavy-up, 5-ton air source heat pump HVAC and water heater, family trained to dry clothes outside :-), 9.69 kW array on the house feeding a 7.6 kW inverter (morning shade), 9.12 kW array on the barn feeding another 7.6 kW inverter (afternoon shade), annual production averaging 15 MWh with consumption marginally less (net metering with price parity typically nets tiny reimbursement from utility plus SRECs). Fun!

      The Bolt sounds like an ideal commuter car, but we recently FIREd with plans to spend time on the road (heading west for a month in late March!) so will continue trading efficiency for convenience until battery technology and charging infrastructure evolves a bit further before replacing our older but bulletproof RAV4 with a PHEV or BEV.

      Curious: why does your hot tub deserve a mention? Ours has a relatively new cover but a typical 1700W resistance heater maintaining 104°F in an enclosed but non-conditioned space. Heat pump heater alternatives are available but very pricey!

      1. Jim, The hot tub is mentioned because my wife “had to have it” and I did not plan that in my plan. Hence the 3 additional panels (easilty added with micro inverters) to my original 40. I have not specifically measured the energy to it, but it is out on the deck exposed to the Maine winter. So I think it is worth mentioning to the engineer that will look at my usage and wonder why it is at 19.7 Mwh. I forgot to add my hotwater heat pump. Just installed Step Warmfloor in my Mbath and soon will put it in my shower floor, seat, and back wall for the Mrs. Low voltage, great product and energy efficient. Maybe next year the kitchen will get a new tile floor and be nice and warm also. EV Silverado may be the next move. Cheers. Kurt

        1. Oh, wanted to add that we just had a -20 night with the following day in the single digits. At -14 my heat pump was still putting out 102.9 degrees of heat. All three kept the house in the high 60’s and we had no need for additional heat. That was an unexpected, pleasant surprise.

  10. I love all the talk about “electrifying” but in my opinion you are not doing anyone in the world any “carbon” favors unless you are making your own power and or reducing your power requirements by switching to something more efficient, for example, like geothermal.
    The grid cannot stand the additional load you are recommending without going to fossil fuels to make the additional power requirements, with nothing said about capacity for the grid. Putting all these electric cars on charging stations at your house only expands the need again for power which will be provided by fossil fuels because they are available, cheap, dependable and you are “demanding” the power now. In fact , hydropower, the most reliable source of non carbon produced electricity, is under fire to be removed from the grid. You can’t have your cake and it too.
    There is no silver bullet and someone needs to remove their head from…… the sand and understand they are asking physics and the current technology to do the impossible. Meanwhile our country suffers because of dreamers, not realists , who live in a bubble who have not woken up and think this is just going to magically happen……just plug it in!

    I’m totally home energy independent with solar but yet on the grid net metering , thank God, because I don’t need an expensive ( nasty carbon foot print) battery array and I’m never without power thanks to the grid and I still give some free KW Hours back to the grid at the end of the year, you’re welcome.

    The math is simple but many refuse to look at it.
    Below is the link to reality.
    https://www.eia.gov/energyexplained/electricity/images/outlet-graph-large.jpg

    Anyone looked at the carbon footprint of those nasty batteries everyone wants in their car or the carbon footprint of a wind turbine and the generator it takes to operate it or the environmental waste left when it needs new blades or new generators. We choose to ignore those realities because it upsets our bubble.
    Not sure those dreamers are ready to conclude the Flintstones had it right and then follow that path.

    1. Have you looked into the microgrid enabling process now collecting 600,000 signatures for the most important ballot initiative ever.
      California
      Renewable
      Energy
      Acceleration
      Law

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