Air Source Heat Pumps

albyota

Somebody call the POLICE...!

stevehead

Here's something I've come across that works well. I've had 3 MHRV's installed recently - MHRV's are Mechanical Heat Recovery Ventilators.
Downstairs, I have a Mitsubishi V100 in the Living Room, and upstairs 2 of the Kair KHRV150's. (Bathroom & Master Bedroom)
Essentially, these devices poke thru your wall, and use a heat exchanger to warm the incoming fresh air with the heat recovered from the outgoing stale air.

Observations so far
The Mitsubishi shifts a lot more air than the Kair. It makes a similar sound to my aircon unit.
Living Room RH (Humidity) has dropped night time. And the air is fresh and warm. I find this very comfortable.
Walking into the bathroom is very odd. I'm used to it being either cold or damp or both due to need to keep the window open all the time after showers. Once the HRV has done it's thing, it's warm and strangely dry in there.

As the windows are no longer open for airing, cold air doesn't permeate the fabric of the house. The retained heat combined with the lower humidity has allowed me to keep the heating off. A degree or 2 lower is perfectly comfy which I reckon is due to the lower RH.

I say complimentary, as if you undertake the process of insulating and draft proofing, then switching on your shiny new ASHP you will soon notice a problem. Where does all the moisture you generate now go? How stale is that air you're breathing? Last winter for me was warm and cheap, but all was not good what with mould & damp & condensation.
A house has to feel good to live in, and I feel that these MHRV's allow you to live in an energy frugal manner whilst still maintaining a high standard of comfort.

richardc1983

Hi Steve

Good to hear from you again I wondered where you had gone!

Were about to fit a 3rd wall mounted unit into the back bedroom which is occupied by my flat mate, he is in here all day and night so needs to be warm for him.

I am one of these people that love fresh air and I will have windows open with heating on and leave them on the catch most of the time just so theres some kind of fresh air coming through even in winter.

The ventilators do sound good, how much did they cost and have you any links, i googled the mitsi one but couldnt find anything.

With my flat being rented I wouldnt look to be installing them here but in my house when i eventually buy I will prob go for something like that.

What is the humidity level in your house maintained at and do you run them 24/7?

stevehead

Hi Rich, well... it was summer so ASHP's etc weren't on my mind much!
The Mitsi I got from Orion - Google 'lossnay vl100' (Sorry, not V100).

Humidity is currently 48 in the Living Room and still maintaining 23.6C with no heating. It's 8C outside.
These things don't allow you to set the humidity you want, they just happen to lower it as it gets colder outside. The colder the air the less water it contains. I can imagine on sunny January days it might get too dry and I'll be needing Lipsil. We'll see.

The Kair units upstairs run on trickle all the time, and auto boost on a humidstat. The bedroom one is absolutely fine on trickle, but it would wake you up if it ever went into boost mode - no thanks.
The Mitsi is on a pull cord. I don't really have a usage pattern Rich, but I expect it'll be on most waking hours over winter.

Yeah.. I don't think the landlord would be best pleased if you core-drilled his flat - homeowners only this one.

richardc1983

Would be good to see a video of how they units look inside and out and where you place them etc. Something similar to the ashp one you did.

48 humidity is actually very low, you might find it very comfortable but its supposed to be about 55%. Skin etc drys out and eyes too! I wear contacts at the air at work is also very low in humidity!

We have bought a dehumidifier to aid in drying washing however it uses more than the air con when its running!

I have broke my foot at the mo so in all day on the sofa not doing much! Going to be off work for 3months and had to have 2 ops on my foot to put it back together.

eugeneg

I wonder how much energy Mechanical Heat Recovery Ventilators consume.

richardc1983

Looking at the units that steve head has above about 26watts!

stevehead

richardc1983 wrote: »

Would be good to see a video of how they units look inside and out and where you place them etc. Something similar to the ashp one you did.

No prob Rich... here you go:
http://www.youtube.com/watch?v=oOvhHmb7Hl8

richardc1983

not working at present will have to wait till later.

albyota

go you film star, steve good video, nice neat job. thanks for the effort.