What size generator does my home need?

Sizing starts with a load calculation, not a neighbor's kilowatt number. The circuits you want on backup set the size for Lakes Region homes.

Load calculation before you pick a size

A proper size comes from the loads you intend to run at once on backup, including motors that surge when they start. Heat, well pumps, and air handlers matter more than a spare bedroom TV. We walk the panel and the house so the generator is not undersized for the list you care about, and not oversized for a short essential set.

Fuel and equipment type change the options

Natural gas and propane standby units have different model lines and cooling types. Air-cooled machines cover many homes. Larger liquid-cooled units show up when the load climbs. We are a certified installer for Generac air-cooled and liquid-cooled systems and KOHLER air-cooled systems. Brand choice sits beside size. See Generac vs KOHLER once the load picture is clear.

Lakes Region houses are not all the same load

A Squam Lake seasonal cottage with a short essential list is a different machine than a year-round Moultonborough or Meredith home with heat, well, and a full kitchen. Detached garages, lower-level panels, and long feeder runs do not change the kilowatt math by themselves, but they change how the sized unit gets installed. Whole-home vs essential circuits should be settled before you lock a size.

This page explains sizing factors. It is for education only. It is not a quote, a diagnosis, or an inspection of a specific house. Request a written estimate for a load calculation on your property.

Liquid-cooled standby generator installed outside a New Hampshire home

Questions

Generator sizing questions for Lakes Region homeowners

Can I size a generator from my electric bill?

A bill shows usage over time. It does not replace a load calculation for simultaneous backup loads and motor starting. We still need the panel and the list of what you want running in an outage.

What if I add an EV charger or a hot tub later?

Say so up front if those loads might land on backup. Otherwise size for today and plan a second conversation when the new load is real. Putting every future idea on the first generator can push you into a larger machine than you need now.

Is a bigger generator always better?

No. Oversizing costs more to buy and install, and it does not fix a wrong transfer setup or a weak fuel supply. Right-sizing to the load calculation is the goal.

Do portable generators get sized the same way?

You still match watts to the circuits on the inlet. Portable setups usually cover a shorter essential list. The house-side inlet and interlock or transfer gear have to match that plan.

Will you put the recommended size in writing?

Yes. A written estimate includes the unit size we recommend, the transfer equipment, and any panel work the calculation requires, before we schedule the job.

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