Electric Bills For Townhouse vs. Apartment

This is a blog post I’ll update as time goes on… But I’ve been wondering how much our utility costs would go up once we moved into a house. Here are the baseline numbers for electrical usage in our old coop. It was 2 bedroom, 2 bathroom, and about 1,350 sq. ft. in a 1939 pre-war (poorly-insulated) building with leaky window A/C units and a Sub Zero fridge:

Summer Average (’07-’09): 29.0 kWh/day
Winter Average (’07-’09): 18.3 kWh/day

Summer I defined as the June 20ish reading through the August 20ish reading. Winter I defined as the September 20ish reading through the May 20ish reading. Actually, winter is a bad term – “non-summer” would be better. So what you see above is theĀ  average of three summers (6 total months), and 2 winters (16 total months)

I should also mention that we work from home – so everything you see includes air conditioning during the day – but typically just for the rooms we were occupying, though Dan has a bad habit in the house of opening doors into unairconditioned spaces and cooling more of the house than is necessary. We also have at least one computer on 24 hours a day – since it acts as a server.

From 5/21 to 6/12 we used an average of 36.3 kWh/day (98% over winter average)
From 6/12 to 7/31 we used an average of 37.2 kWh/day (28% over summer average)
From 7/31 to 8/20 we used an average of 54.1 kWh/day (87% over summer average)
From 8/20 to 9/20 we used an average of 41.0 kWh/day
From 9/20 to 10/23 we used an average of 31.4 kWh/day (72% over winter average)

Now, mind you, the house is a lot bigger has more things going on. Instead of 1,350 sq. ft., it’s about 3,200 sq. ft. There’s 180 watts of light bulbs that are on from dusk to dawn (roughly 2 kWh/day). There’s a dehumidifier running the cellar 24/7 – it’s Energy Star certified, but it still uses a fair amount of power. The server we have running is more power hungry. There’s also a booster pump for water pressure, etc. All in all there’s just more electrical demand than there was in the apartment.

The average from 6/12 to 8/20 was 42.1 kWh/day. Since the period started a little earlier than it should have and there were some days we wished we had A/C before July 3 (when it actually got up and running), let’s call the summer average 45 kWh/day – that would be “just” 55% more than at the coop. I’m pretty happy with that, all things considered.

The average up to 6/12 and after 9/20 is 33.4 kWh/day. So once again we see power going up roughly 11 kWh/day for A/C during the summer. That’s great since we’re cooling more space than we did at the apartment with about the same amount of energy. In fact for about 6 weeks during that time Dan had the A/C on 24/7 up in the studio because he was making stuff out of fiberglass and needed to control the temperature. But our building is more efficient and the A/Cs are more efficient.

But the “winter” (non-summer) power is considerably higher. So far, the townhouse seems to consistently use 15 kWh/day more than our old apartment – that’s 80% more power. Electricity seems to be costing about 25 cents per kWh, so that’s less then $4/day, or about $115/month additional. But when you look at the list of stuff (above) that we didn’t have in the old apartment, it sorta makes sense that it costs more to run a townhouse that’s over twice the size of the apartment.

We also have data for our tenant. That’s a roughly 1,050 sq. ft. duplex apartment (basement & half of the cellar):

From 7/31 to 8/20 he used an average of 24.5 kWh/day (15% under summer average)
From 8/20 to 9/20 he used an average of 35.2 kWh/day
From 9/20 to 10/23 he used an average of 20.9 kWh/day (14% over winter average)

Our tenant also works from home. Theoretically his energy usage should be less than our old apartment – the square footage is less, the insulation is better and the A/C is more efficient. Plus, a third of the space is the cellar which almost never needs cooling. But he does have a dehumidifier running 24/7… His usage was 15% below our usage from late July to late August, but then the following month his electricity usage went up considerably for some reason. And then he was 14% over our winter usage in the past month.

5 thoughts on “Electric Bills For Townhouse vs. Apartment

  1. Not sure you are accounting for the fully loaded cost of energy in your last apartment. Since you paid common charges in your coop / condo, you were probably paying for the common area lights, dehumidifier, etc. for the building with your monthlies. It would bridge the gap, but those things cost money to things were likely part of your common charges.

  2. What did you do for soundproofing between renter and you? We are going back and forth with contractor & architect : homasote board v double OSB v sound mat. It’s foot falls we worry about. 3 kids. We don’t want scare away good renters.

  3. Karen – That’s covered in my blog post on sound proofing. I’m not sure if our tenant is just quiet but we rarely ever hear him. He does hear us a bit. Mostly on the stairs – the stringers are welded to the joists – so the sound on them travels a bit.

    Also, don’t forget to soundproof your boiler room – the stuff in it is louder than you’d think.

    • what did you put down as the underlayment for the wood floors?
      we are doing a naildown hardwood – blown cellouse and the ceiling below is already a floating ceiling: its not connected to the floor joists above.
      contractor is still saying homasote board is good idea…
      by the way – I had asked you about a commerical oven – many months ago.. the DOB answer was – if the manufacturer says its approved for residential use it will pass code.. so the one we bought did not … so it was an expensive lesson to learn..

      Thank you and keep up the great information.

      • From top to bottom we have:
        – Hardwood floor
        WhisperMat HW
        – 8″ metal joists pretty much filled with open cell foam
        – Resilient channel hangers (in tenants bedroom only)
        – 2 layers of 5/8″ sheetrock

        If I had it to do all over again I’d use resilient channel everywhere – it makes a real difference.

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