Resource for average power consumption for common household items?

[iamrich]

I did a search and didn't find much. Does anyone have a good resource for power consumption of items like electric stoves, heaters, heat pumps, etc.? I have all natural gas items right now, so I can't just throw a watt meter on them. Trying to fill out a theoretical energy audit for my next house, but I have never had electric appliances.

 

[sunshine_eggo]

This site's off-grid calculator makes some guesses:

Off Grid Calculator | Solar Biz

www.thesolarbiz.com

 

[Dzl]

Energy star ratings can give you a ballpark of yearly which can be convered to daily, but won't give any indication of max draw, and its not always clear what assumptions energy star uses and not always easy to find out.

 

[Hedges]

How To Use the EnergyGuide Label To Shop for Home Appliances

The more energy efficient an appliance is, the less it costs to run, and the lower your utility bills might be.

www.consumer.ftc.gov

 

[MichaelK]

A lot of times, I just go to the HomeDepot website, and look up what I'm interested in, and then click on "specifications". I usually will get a "running watts" value for just about anything I look for.

 

[iamrich]

Thank you all for the links. It is challenging figuring this out as I don't know what models I will be using.

 

[Isaac-1]

Keep in mind many of these lists are outdated to say the least, as often these list are simply reprinted from older reference lists that fail to take into account changes in power consumption by various appliances, TV's are a good example one such chart I found online lists 100 watts for a 13 inch TV and 200 watts for a 27 inch TV, these sorts of numbers have not been true since the age of tube TV's. Even with flat panel TV's the power draw is dropping every year, though I have to question how much lower can it go. To put this in perspective I bought a 24 inch smart TV for my RV last year, which has a max power draw of 25 watts, it replaced an older 2008 model flat panel non smart TV of about the same size (22 inch) which drew 68 watts max, and the 2018 smart tv model which which was its immediate predecessor in the brand /model lineup drew up to 38 watts.

Light bulbs is another issue, the old style 60 watt incandescent light bulb drew, well 60 watts, the modern LED 60 watt "replacement" bulbs draw about 9 watts to output the same amount of light, and if you still have them the Compact Florescent 60 watt "replacement" bulbs draw about 13 watts.

 

[iamrich]

Yeah, I will take the ratings with a grain of salt. My biggest concern is figuring out how much power I need to run everything in the worst possible scenario. 1.5 Ton AC is cranking away, 240v water heater flips on, garlic bread is cooking in the 240v oven, spaghetti boiling on the 240v stove, sauce heating in the 120v microwave, 120v refrigerator pumping away, 120v washer doing its thing, 240v dryer drying, tv blaring, computer cranking away, and all the LED lights on in the house. Will that likely happen? I hope not, but I have to plan for it.

I have a solid plan for the solar array (15kw+optional 10kw more on the garage), batteries (30kwh 48v LiFePo4), and the grid (split phase 120/240V/60hz 200amp). Just need to figure out the inverter(s). The main goal is to be able to power everything seamlessly if the grid goes down for a bit (couple days), and power everything essential indefinitely (zombie apocalypse). Not looking to sell power back or feed the grid, just have rock solid power 24/7.

 

[MurphyGuy]

Do not believe any website that lists power consumption specs for household appliances.. they are all over the board.

Microwaves can be anywhere from 400 to 1800 watts.
Televisions can be anywhere from 100 to 600 watts.

About the only thing that would be accurate are maybe electric clothes dryers, standard 40gal water heaters, and maybe a few other appliances.

And don't forget about the wall-wart power supplies for all your gadgets.. those damn things add up fast.

Best thing you can do is get a kilo-o-watt meter.. or just clamp a wire from a breaker to see what its drawing.

 

[sunshine_eggo]

Yeah, I will take the ratings with a grain of salt. My biggest concern is figuring out how much power I need to run everything in the worst possible scenario. 1.5 Ton AC is cranking away

Not so much the run power, but you REALLY need to look at the LRA or surge of the compressor. They are brutal. This alone can seriously drive your inverter selection. There are soft starts (MicroAir) available for residential A/C up to 3 ton I think? Mandatory to install one.

, 240v water heater flips on

4500W typical

, garlic bread is cooking in the 240v oven

Typically cycles 3500W depending on oven.

, spaghetti boiling on the 240v stove,

Varies, but 1500W on the low end.

sauce heating in the 120v microwave,

1600W consumed for 1000W output

120v refrigerator pumping away

meh

120v washer doing its thing

Not sure, but on a heavily loaded circuit in our house, starting the washing machine is usually what kicks the breaker over the edge...

, 240v dryer drying

3000W

, tv blaring, computer cranking away, and all the LED lights on in the house.

Meh.

Will that likely happen? I hope not, but I have to plan for it.

Yes you do.. it will. Especially your kitchen scenario.

I have a solid plan for the solar array (15kw+optional 10kw more on the garage), batteries (30kwh 48v LiFePo4), and the grid (split phase 120/240V/60hz 200amp). Just need to figure out the inverter(s). The main goal is to be able to power everything seamlessly if the grid goes down for a bit (couple days), and power everything essential indefinitely (zombie apocalypse). Not looking to sell power back or feed the grid, just have rock solid power 24/7.

Nice!

 

[iamrich]

Best thing you can do is get a kilo-o-watt meter.. or just clamp a wire from a breaker to see what its drawing.

Yeah, this part is killing me. I don't own any of the items (yet) or it would be a lot easier. I have all natural gas in my current house.

Not so much the run power, but you REALLY need to look at the LRA or surge of the compressor. They are brutal. This alone can seriously drive your inverter selection. There are soft starts (MicroAir) available for residential A/C up to 3 ton I think? Mandatory to install one.

Now that I am thinking about it, the water heater and laundry are right next to each other in the house design. I think a stand-alone inverter for those items might solve a lot of worry. If the system fails (trips a breaker) it's not that critical, and it will not take everything else with it.

 

[MurphyGuy]

Yeah, this part is killing me. I don't own any of the items (yet) or it would be a lot easier. I have all natural gas in my current house.

Now that I am thinking about it, the water heater and laundry are right next to each other in the house design. I think a stand-alone inverter for those items might solve a lot of worry. If the system fails (trips a breaker) it's not that critical, and it will not take everything else with it.

Go get a Killowatt meter, they're $30 and money well spent.

If you check your local craigslist or facebook, you might be able to find a good used one for $10.

If you're trying to get an over-all picture of your energy usage, I would highly recommend an IotaWatt.. You could just get the basic unit and the two main wire clamps and it will tell you how much energy you're using per day, week, month, etc.. and when you're using it.

 

[iamrich]

Go get a Killowatt meter, they're $30 and money well spent.

If you check your local craigslist or facebook, you might be able to find a good used one for $10.

If you're trying to get an over-all picture of your energy usage, I would highly recommend an IotaWatt.. You could just get the basic unit and the two main wire clamps and it will tell you how much energy you're using per day, week, month, etc.. and when you're using it.

Oh I have a killowatt meter, I just don't have the electrical items I need to measure yet. The house hasn't even broken ground.

 

[12VoltInstalls]

The house hasn't even broken ground.

the water heater and laundry are right next to each other in the house design. I think a stand-alone inverter for those items might solve a lot of worry.

Not looking to sell power back or feed the grid, just have rock solid power 24/7.

I’d seriously consider a propane kitchen stove, dryer, and demand hot water heater.

You can have an electric hot water pre-heater storage tank ahead of the demand propane. Excess solar will likely be able to make all your hot water most of the time but cloudy days / stormy periods will be less of a concern.
Basically they rest of the house won’t require so much upfront cost and still be sufficient.
Some have done a propane range with an electric cooktop or range right next to it so you can choose to use the most optimal energy source at the moment.

 

[iamrich]

I’d seriously consider a propane kitchen stove, dryer, and demand hot water heater.

My Mom nixed that idea right at the start and she if footing the bill, so... All Electric is the plan. The good news is that I have a decent budget set aside for the job, I just have to make sure what we get will do the job.

 

[Hedges]

Propane BBQ or camp stove. That's backup for when battery charge is low, and portable for camping/tailgating.

I think an electric water heater as diversion load is good to store surplus energy, and that can be used to start cooking some dishes.
Typical stove has an uninsulated pot on top losing heat to the room. Something like an insulated crock pot would maintain cooking temperature with much less energy consumed.

Typical electric dryer dumps all heat outside. Air to air condensing, if it uses the preheated air from exchanger, should consume less. Heat-pump dryers.

During summer you would have plenty of electricity, but for winter and cloudy days good to have a battery status signal, and choose when to do laundry and what type of cooking according to available power.

Starting from nothing, you should be able to select appliances with 4:1 to 10:1 reduction in energy consumption, also limit starting surge.

But what do you plan for central heating? Very difficult to do that with solar during winter if a cold climate.

 

[iamrich]

Starting from nothing, you should be able to select appliances with 4:1 to 10:1 reduction in energy consumption, also limit starting surge.

This I hope to do and will be paying attention to what we buy.

But what do you plan for central heating? Very difficult to do that with solar during winter if a cold climate.

That plan right now is to have a 1-ton AC/Heat Pump on Mom's side of the house, and a 2-ton AC/Heat pump on my side of the house. They will be completely independent, and she likes it a bit warmer year-round than I do. I am in Central Texas (just east of Austin), so the weather is very mild. Our snowmeggedon this year had temps as low as 6F which brought us to our knees but that would be a pretty nice day for a lot of the country in winter. Normal winter temps are mid 30s during the night, but right back up to 50-60s during the day.

Worst case we just use grid. I plan to have 120/240/60hz 200amp grid in the mechanical room. I obviously I would prefer not to use it if I don't have to, but as I mentioned I am looking for 100% reliability.

 

[Hedges]

Worst case we just use grid. I plan to have 120/240/60hz 200amp grid in the mechanical room. I obviously I would prefer not to use it if I don't have to, but as I mentioned I am looking for 100% reliability.

In that case, assuming reasonable net metering is available, I recommend installing 3x the PV and zero battery. (At least for my rates, where peak is 3x off peak.) PV is cheaper than batteries.

Only enough battery for convenience during power failures. Maybe it would be feasible to have thermal storage. That could be a slab/gravel mass insulated from earth (slow drop in temperature as energy is released) or a more active system storing thermal energy at higher temperature and releasing it to keep house warm. Insulated cargo container full of gravel, with air duct to exchange heat? Hot water tank with hydronic floor and/or radiator heating? Hot water tank as source of heat for your heat pump would be another idea.

In a pinch batteries can power mattress heating pad (more effective than electric blanket on top.) Note that those things can be a fire hazard.