What are the biggest electricity consumers in a typical home?

As a baseline, consider that typical homes in the United States consume on average 30–60 kilo-Watt-hours (kWh) of electricity per day (=900–1800 kWh per month) at a cost of $0.10-$0.20 per kWh. Those running on electric heat often double these numbers.

  • In homes with electric heat, the heater can dominate all other electric consumers. Heat pumps, while considerably more efficient (1/3 – 1/2 the consumption) than straight electric resistance heat (like an electric baseboard heater) still consume substantial amounts of electricity. Consider that a typical heat pump system uses 3kW – 6kW while running, daily consumption in cold days can easily be 30–60kWh or more. This is why home insulation and air-tightness is such an important way of conserving energy. Same is true if the home is heated with oil, gas or propane – home heating and cooling costs dominate all others, so a tight, well insulated home pays dividends year after year.
  • Electric water heater – consumption varies drastically depending on a family size and hot-water usage. But an average is about 400 kWh per month. A modern heat-pump water heater can cut this in half.
  • Refrigerator/freezer – older units were much less efficient than a modern, EnergyStar unit. A typical range is 40–80 kWh/month.
  • Lighting – with the advent of energy efficient LED lights, this has shifted considerably. A home that has the equivalent of ten, 100W bulbs running 12 hours/day uses 12kWh per day or 360kWh/month. If all those bulbs were replaced by 14W LED bulbs that put out the same amount of light, that would be reduced to 1.7kWh/day or 50kWh/month. Lighting is an area where every home can dramatically reduce consumption by replacing conventional bulbs with LED in high use locations like the kitchen and living rooms.
  • Air conditioner – central air conditioners and their blowers consume from 3–7 kilo-Watt-hours (kWh) per hour of operation.
  • Home electronics – computers, DVRs, TV, stereos all add to a home’s use and together add up to 200W-1000W/hour, every hour. Typical consumption is 4–10kWh/day or 120–300kWh/month.
  • Cooking – electric ranges and ovens consume 2kW–4kW while running and might be operated for an hour or two per day on average.

Other items that add considerably to electric bills but are less common:

  • Pool pumps – most are drastically oversized and run 12 hours a day. A typical pump uses 2500W, so that’s 30kWh/day or 900 kWh/month! Replacing that with a two-speed or variable speed pump can cut this by 75% – well worth the investment.
  • Spas/Hot tubs – outdoor hot tubs use about 6–15kWh/day, depending on usage, design and temperature, call it 10kWh on average. That’s 300kWh/month. Since many people don’t use their tubs during the winter, it pays to shut it down for the winter, saving about $50/month.
  • Ponds – ponds have become very popular in the suburbs but most people don’t realize how much they cost to run. Those waterfalls require larger pumps, consuming 500W–1000W while a basic pond filter pump might use 100W-250W. Consider an average of 500W for 24 hours is 12kWh per day or 360kWh/month.

It’s extremely educational to install a whole-house energy monitor or use an inexpensive plug-in energy monitor to see how much energy each of your devices consume. But watch out, once you do, you may turn into a true energy geek, like me 🙂

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Q&A – Should I get a high efficiency heat pump?

A friend dropped me this email yesterday, asking for some advice (slightly edited):

We spent a lot on oil last winter.  We have a 23 year old heat pump which gives us A/C in the summer, but no heat any longer.  I had a proposal from the installer for a new 14.5 seer heat pump replacement.
Here is the question: how much more efficient will that unit be compared to our old unit?  We are not convinced that it is worth the cost, so we thought you might give us a ball park estimate of potential savings.  Bottom line is enough: does this sound like a good decision?

This is such a great question, that I wanted to share it, and my answer, with the rest of you.

Let’s start with the basics – what is a heat pump?

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