Portable AC or window AC for a Washington house?

What it costs, with dates

Neither type comes with an official price we could find, so no purchase or installed figure appears here. Compare listings on equal capacity.

Running cost is a sum you can do from the label. Washington residential electricity averaged 14.63 cents per kWh in August 2026, and Seattle City Light's flat rate is 13.38 cents plus a daily base charge. Take the watts on the label, divide by 1,000, multiply by hours and by your rate. As our own example, not a measured figure, 1,000 watts for 8 hours is 8 kWh, about $1.17 at 14.63 cents.

We found no rebate aimed at portable or window units on the utility heat pump and weatherization pages checked for this site, as of November 2026. Confirm with your utility. If you end up hiring an electrician, get the bid in writing and have it itemize the circuit work and the permit.

Who does the work

A portable needs no installer. A window unit must be secured exactly as its manual says; if the sash or sill is doubtful, have someone qualified fit it or choose a portable. Your part after that is clean filters, clear airflow around the unit, and checking a breaker if the unit goes dead.

If a breaker trips repeatedly, stop there and call an electrician. L&I says you must purchase a permit before starting any electrical work, and you can verify any contractor on L&I's tool. See who pulls the permit.

Don't open either unit. EPA requires certified technicians for equipment that could release refrigerant, so a unit that has lost its cooling goes to a shop or gets replaced.

Does the number of hoses matter in smoke season?

Yes, at least in EPA's advice. EPA separates the two: a single-hose portable should be used sparingly because it can bring more smoke in, and a two-hose unit should have a tight seal.

That matters here because Washington DOH says smoke season typically starts in July or August and can begin as early as May.

Neither machine should be treated as your smoke filter. EPA notes that window units typically lack filters for PM2.5 and says to add an air cleaner. Its guidance on that point doesn't mention portables, so plan on the same. The sizing is on HEPA cleaner or MERV 13 filter.

How do you size a room unit without guessing?

Start from the room's square footage and adjust. ENERGY STAR's sizing assumes an 8-foot ceiling, takes off 10% for a heavily shaded room, and adds 600 BTU per person over two.

Bigger is not safer. The same page warns that an oversized unit leaves the room damp and clammy. For a portable, we found no equal guidance, so go by the maker's label and don't assume the two match.

Is one of these enough for the next heat dome?

It can cool a room, with no guarantee. Sea-Tac reached 108F on June 28, 2021, and Yakima's record of 113 came the next day. A unit that keeps up on a normal day may fall short then.

Have a fallback. EPA says to consider shelter elsewhere if you can't stay cool at home, the power goes out or too much smoke is getting in. In Washington, dial 2-1-1 for cooling centers. For the rest of the plan, see the no-AC house, or the west side and east side overviews.