A:Answer Hello there, this is Kelly with Dyson. We don't measure our machines in terms of BTU's. While our machines do have a heating element, they're measured in watts. While in heat mode, the purpose is to provided heated, purified air in to your room. How well it heats your space would vary, depending on factors such as doors and windows, how warm the room already is, the air temperature outside, etc. With our Dyson Pure Hot+Cool™ purifiers, you can set the desired air temperature all the way to 99 degrees, and you have 10 airflow speeds to choose from.
Best wishes,
Kelly
Dyson Customer Support