Technical > Home Improvement > whole house generator

whole house generator

You definitely need more than that if you want to run A/C.

I would say 15-20kw at least.

The water softener doesn't use much electric. In fact mine is powered from a wall wart.

10k is definitively not enough.
Anyway, if he's willing to drop the $$$$ on the whole installation, I don't think the price to go from 10kW to 20kW is a big deal.

Just checking out on the Canadian Costco website:

10kW - 2800$
15kW - 3600$
20kW - 4900$

He's already gonna need to spend a lot of money on the installation, and god knows what he'll need to do to hook it up to NG or propane.

reply to Zorack
10KW seems low. They are only recommended for 3 ton AC.

~17kw seems to be what is recommended for 5 ton AC. I'd go with 20kw to be on the safe side. The price difference is minimal.

Does he have an electric water pump or electric water heater?

reply to Zorack
Installation of a whole house genny is about 10 grand up here. It's only about $500 difference for a 20kw vs a 12kw unit.

The big difference is going to be fuel consumption.

reply to Zorack
He should have an electrician come in and figure out what the load will be on the generator.

reply to Zorack

reply to Zorack
Before considering a big generator, check if you have a gas supply big enough. If they have to run a bigger gas line from the street and add a higher pressure regulator, the cost can be huge. I have seen $20k to run the gas line.

My 8kva Generac works fine. I don't run the main A/C but i have a window shaker in my office that works fine.

reply to Jack_in_VA
That's because there is more BTU per cubic foot with propane than NG.

For cooking/burning that's not a big issue, you just have bigger holes to let more NG come out.

However, for an engine, there's a limited amount of fuel that can enter the cylinder, so basically the generator on NG will run on "weaker" fuel.

reply to Zorack
Installation of a whole house genny is about 10 grand up here. It's only about $500 difference for a 20kw vs a 12kw unit.

The big difference is going to be fuel consumption.

reply to Zorack
Yeah, my 14kw propane genet turns into 12kw if run on NG.

I ran my 4 ton AC over the summer just fine...

reply to Zorack
Note, not all generators are rated lower on NG than LP. The manual on mine does not mention any de-rating for NG. Probably because it has a 25HP engine (run at lower speed) while most 8KVA would use 12-15HP.

reply to KirkyInCT
so does the whole house generators run on NG and LP. as in it will do either or without changing anything.

this would be good if lets say th gas company had to shut off the gas. could go get a 100lb LP tank and hook it up in place temp until natural gas came back

I would bet nearl all can run on LP or NG. Mine has a regulator block with 2 ports. To switch between the NG/LP, you swap the hose to the engine between the two ports.

I have been in this house for 22 years. I loose power often due to storms, at least once a year more than 8 hours (lots of trees who's dying wish is to take out that power line.) I have never lost NG.

reply to Zorack
Make a list of the following:

Service entrance rating determines the maximum amount of power that can be provided by the Power Company. 100 Amp = 24KW, 150 Amp = 36KW and 200 Amp = 48 KW. No use buying a 48 KW generator if the house has a 150 Amp Service entrance.

Type of fuel available:

If you want to use propane - Make sure that the propane tank meets the draw down requirements of the generator. Most generators require at least a 250 Gallon tank. If you have propane determine who owns the tank. If your son owns the tank make sure they do not replace a customer owned tank with a leased tank.

If you want to use Natural Gas, I agree with shdesigns that your son should contact the Natural Gas supplier and ask them if they can supply sufficient NG to meet the requirements of the proposed generator. Make sure you find out the BTU's per hour required by the generator and then advise the gas company of that requirement. They should be able to tell you if the gas line supplying the house can deliver the required fuel.

If fuel oil is used for heat consider installing a diesel generator although they are more expensive compared to air cooled propane/NG generators.

Make a list of the fuel source of each appliance. If your son is renovating the home and he has natural gas or propane available, consider replacing electrical appliances with gas appliances to reduce the load on the generator.

Typical power requirement for appliances:
Electric Range up to 18 KW.
Electric Dryer up to 6 KW
Electric Water heater up to 6.5 KW
Electric heat can be any value depending on the size of the home.
AC straight cool 60,000 BTU (5 Ton) depending on efficiency can be up to 8 KW. Heat pumps have a much higher power requirement because the heat strips are run concurrently with the compressor during the defrost cycle.

Most air cooled propane/NG generators require a modification to the fuel system to change fuel type. Failure to make the change can damage the engine.

I compared the fuel requirements of a 10 KW Generac air cooled generator operating at full power to a 20 KW Generac air cooled generator delivering 10 KW. 10 KW Generator uses 1.93 Gallons per hour while the 20 KW Generator uses 1.89 Gallons per hour.

Once you have obtained the necessary information, have a reliable generator dealer determine the proper generator for your needs.