Any advice on heat recovery fans from Vent Axia and how good thier "h" humidity function works?

[diy_massacre]

Crossed wires here. It will monitor the air inside the room. However, the air in the room will be replaced with outside air which may have a high RH. So the 'new' air in the room may also seem damp to the sensor. The fact that your fan will preheat the incoming air will certainly help it distinguish, however, the very act of heating the air will cause the RH to fall somewhat.

Hi Ric2013

Yes understand your point, thanks for the clarification. Think I will get one anyway even if it overruns sometimes.

Many thanks

diy_m

 

[gmartine]

I don't expect the average person to understand so no point in discussing that with you

Back with your condescending replies again?

It depends what percentage of heat is recovered and if you need constant operation. If the fan consumes 5W of electricity and is run constantly, that's 0.13kW per day.

But 9l/s is 32cu m. an hour. So you could be changing all the air in the room once per hour at that rate.

As far as I can gather (very roughly indeed), it takes around 1.2W to heat a cubic meter of air by 1°C. So at 20°C indoors and 10°C outdoors, every day would have 770 cu m x delta 10 x 1.2W = 9.2kWh. Recover half that energy and you've saved 4.5kW. Nearly a pound's worth of electricity if you're a low energy user or on a genuinely green tariff.

So, assuming the fan lasts only 3 years, and assuming a 100 day heating season it is still paying for itself compared with just opening the window. So not a stupid idea at all.

I have no problem with the principle of heat recovery just the thought of using an extractor fan designed for a high humidity environment like a bathroom being used in a room that it isn't designed for. The issue is the hex's on these particular fans are usually triggered by humidistat that can be set but not at a level that is applicable for say bedrooms as is being preposed not to mention the noise emanating from them also makes them inappropriate.

Vent Axia 370363 HR30W Heat Recovery Unit 50m3/hr 70% Efficiency

Vent Axia 370363 HR30W Heat Recovery Unit offering 50m3/hr extract and 70% HR Efficiency. Designed for use in domestic ventilation and extraction. NOW ON SPECIAL OFFER!

www.extractorfanworld.co.uk

You're welcome.