4 August

Interesting experience yesterday. Now the fans have all gone from the room we were drying, we left the heating on in there all day, just a small 2.5 kW reverse-cycle unit. Ventilation guy said warmth and humidity about 40% is optimum for drying any moisture that's left. What we weren't expecting was that this actually heated the whole house to a toasty warm. And it stayed that warm pretty much all night, even though it got to -4 overnight. (Turned the heater off before bed). Normally we'd turn on reverse-cycle units in other parts of the house as well, but we didn't need to yesterday. It'd be interesting to see whether leaving a single heater on all day would be a more efficient strategy for us than using multiple units at the end of the day. The single unit uses less than 1kW when running. I wonder if some of the heat got stored in the thick walls. It definitely keeps moisture levels down, just raising temperature decreases humidity, even if the amount of moisture in the air is unchanged. This is a debating topic in the UK apparently, whether to leave a heater on low all day or just when you're there. Generally it will be less efficient to leave it running all day, because houses leak heat. But with the new windows and double-brick walls, it's an open question in ours. The same may also apply for cooling in a hot summer.