You do not need a big house to use a whole house fan. A small fan can cool a cottage, an ADU, or the one bedroom that never cools down.
A small whole house fan works in small homes, ADUs and single rooms, as long as there is a vented attic above the ceiling. The CentricAir 1.5 moves 1,263 CFM on 143 watts, fits a 14 by 14 inch ceiling opening, and needs 1.75 square feet of attic vent area. CentricAir’s sizing guide lists it for spaces up to about 700 square feet.
Small spaces heat up fast and cool down slowly, especially rooms over a garage or tucked under the roof. A full size whole house fan would be overkill, and its larger ceiling opening may not fit. A small fan sized to the space does the same job at a lower cost to buy and run.
Where does a small whole house fan make sense?
Anywhere small with a vented attic above it.
- Small homes and cottages. Single story homes under about 700 square feet.
- ADUs and guest houses. Detached units with their own attic.
- One hot room. A bonus room, upstairs bedroom or converted attic space that stays hot after sunset.
- Top floor condos. Only with an attic above and your association’s approval.
How do you size a small whole house fan?
Start with square footage. CentricAir lists the 1.5 for spaces up to about 700 square feet.
That covers a small cottage, an ADU or a single hot room. In a smaller room, run the fan on low, where it moves 793 CFM and runs quieter. If the space is larger than 700 square feet, step up to the CentricAir 2.0, listed for single story homes up to 900 square feet.
| CentricAir 1.5 | CentricAir 2.0 | |
|---|---|---|
| Airflow, high / low | 1,263 / 793 CFM | 1,918 / 1,049 CFM |
| Power | 143 W | 207 W |
| Cost per hour at 18.2¢/kWh | about 3¢ | about 4¢ |
| Noise, high / low | 47 / 45 dBA | 48 / 47 dBA |
| Ceiling opening | 14 x 14 in. | 14 x 20 in. |
| Attic vent needed | 1.75 sq ft | 2.5 sq ft |
| Weight | 35 lb | 40 lb |
| CentricAir sizing guide | Up to about 700 sq ft, single room | About 900 sq ft one story, 1,400 sq ft two story |
| Price | $849 | $1,049 |
From CentricAir product pages and sizing guide, September 2026. Prices are the listed sale prices, before installation, and may change.
What does your attic need?
Room to hang the fan and enough vent area for the air to leave.
CentricAir’s installation video calls for about 30 inches of clearance above the ceiling spot and at least 14 1/4 inches between joists. The 1.5 needs 1.75 square feet of net free attic vent area. Without enough vent area, CentricAir warns, pressure builds in the attic and air can be pushed back into the living space.
Do small new homes need a whole house fan in California?
Not if they are 500 square feet or smaller.
California’s energy code includes a whole house fan in the prescriptive path for new single family homes in climate zones 8 through 14, but new dwelling units of 500 square feet or less are exempt. Anything larger in those zones should be checked with your builder or energy consultant. See our California guide.
The CentricAir 1.5: 1,263 CFM on 143 watts.
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Frequently asked questions
What is the smallest whole house fan?
In the CentricAir line, the CentricAir 1.5: 1,263 CFM on 143 watts, with a 14 by 14 inch ceiling opening.
Can you put a whole house fan in a small house?
Yes, if there is an attic above the ceiling to exhaust into and enough attic vent area. CentricAir’s sizing guide lists the 1.5 for spaces up to about 700 square feet.
Can a whole house fan cool just one room?
Yes. Install it in or next to that room and open that room’s windows. CentricAir’s sizing guide lists the 1.5 for single room use.
Can I put a whole house fan in a condo?
Only in a top floor unit with an attic above it, and with your association’s approval. The fan has to exhaust into a vented attic.
Keep reading
Sources
- CentricAir 1.5, 2.0, 2.7, 3.4, 4.0 and 4.0 ECM product pages (specifications tab), centricair.com, accessed Sept. 30, 2026.
- CentricAir, What size house fan do I need?, accessed Sept. 2026.
- U.S. Department of Energy, Building America Solution Center (PNNL), Whole-House Fans, updated Sept. 29, 2022.
- CentricAir, CentricAir and QA-Deluxe Whole House Fan Installation Video, YouTube, May 12, 2015.
- California Energy Commission, 2025 CF1R-NCB-01-E Prescriptive Newly Constructed Building form, and 2022 Energy Code Section 150.1(c)12, Whole House Fans (Energy Code Ace).
- U.S. Energy Information Administration, Short-Term Energy Outlook: Electricity, released Sept. 9, 2026.