MHRV required with Heat Pump

Curious Geroge

Started our new build and we're looking to install a Heat Pump. We're well insulated, plans to put in the air tight membrane and in the process of ordering windows. We seem to have choices here, adding air vents to the windows or installing MHRV. Since we're looking to be air tight the vents don't seem appropriate but I wondered if MHRV was a requirement ? They seem overly expensive to install (5/6k) and have a running cost of about €180 a year. I'm interested to know if its worth it ? Thanks

fairwind

Curious Geroge wrote: »

Started our new build and we're looking to install a Heat Pump. We're well insulated, plans to put in the air tight membrane and in the process of ordering windows. We seem to have choices here, adding air vents to the windows or installing MHRV. Since we're looking to be air tight the vents don't seem appropriate but I wondered if MHRV was a requirement ? They seem overly expensive to install (5/6k) and have a running cost of about €180 a year. I'm interested to know if its worth it ? Thanks

hi there
no is the short answer unless you are going passive.
we are building a new a2 house and fitting heat pump and whats called a demand control ventilation -basicly simple motor that sucks air out but no filters etc to change and responds to human presence and humidity basic cost of system is circa 2 m but u need an installer.aereco do it.
f

fclauson

careful here

check out Part F regs - make sure you ventilation complies

If you are going airtight (below 3 ACH) they you will need an MVHR

Having now lived in a house for 6 months with it I would not be without

JD6910

airtightness and ventilation go hand in hand.

no ventilation - expect mould etc.....

Curious Geroge

Thanks guys.

afinador

Hi guys

Hope the build's going well George...

we're doing a retrofit to a 70's semi-d, and aim to get to passiv standard. Builder well up to speed with what's involved, and reasonably confident of getting an ACH of .6 .

There'll be an HRV system and a heat pump, but we're struggling a bit with choice of heat pump (air to water) anyone know anything about the Panasonic Aquarea range? How does it hold up in hard frost?

Any comments appreciated

Tommyboy08

afinador wrote: »

Hi guys

Hope the build's going well George...

we're doing a retrofit to a 70's semi-d, and aim to get to passiv standard. Builder well up to speed with what's involved, and reasonably confident of getting an ACH of .6 .

There'll be an HRV system and a heat pump, but we're struggling a bit with choice of heat pump (air to water) anyone know anything about the Panasonic Aquarea range? How does it hold up in hard frost?

Any comments appreciated

None of the jap units holds up well in hard frost, are your installers recommending you fit a buffer tank to help defrosting, is it all underfloor, have you looked at ground source at all, more expense but lasts twice as long and much lower running costs

afinador

Tommyboy08 wrote: »

None of the jap units holds up well in hard frost, are your installers recommending you fit a buffer tank to help defrosting, is it all underfloor, have you looked at ground source at all, more expense but lasts twice as long and much lower running costs

Not using underfloor- dug out the floor and loads of insulation below slab. Half of the downstairs will be a workspace for me, and I work with pianos, so UFH a complete no no. Can't do ground source because of neighbourhood.
Installer recommending 200l tank and 'volume' tank (is this the same as a buffer?). Looking at 1 rad in upstairs bathroom and 2 rads downstairs. Space heat requirement should be v low. Smart rads or standard?
Can ext HP be insulated/housed to keep it happy in Winter or does that compromise air flow?

hexosan

If you can't use ground source due to the neighbourhood have you looked at radial drilling. There's one company I know of that can drill in even the tightest of sites. I can PM their name to you.

afinador

hexosan wrote: »

If you can't use ground source due to the neighbourhood have you looked at radial drilling. There's one company I know of that can drill in even the tightest of sites. I can PM their name to you.

Wow, that looks fantastic, but we really have very little space, and restricted access- it looks like a big enough rig on site to drill.Also a lot of granite on site so drilling will be longer and more expensive. Our initial enquiries had ground source as having a significantly higher instal cost, and not massively cheaper running costs- particularly for a small house without ufh- so recovery time for outlay would be substantially longer, no?
What's your take on conventional rads v smart rads?

hexosan

afinador wrote: »

Wow, that looks fantastic, but we really have very little space, and restricted access- it looks like a big enough rig on site to drill.Also a lot of granite on site so drilling will be longer and more expensive. Our initial enquiries had ground source as having a significantly higher instal cost, and not massively cheaper running costs- particularly for a small house without ufh- so recovery time for outlay would be substantially longer, no?
What's your take on conventional rads v smart rads?

I looked at this rig in operation on a site in Athy, Kildare end of last year. Its actually quite a small rig up close and you'd be surprised where they can fit it. I'm just not sure of the benefits of radial over vertical. If you believe the salesman it's the bees knees, but then isn't it always.

Not sure about rads as I haven't looked into this as I'm going with UFH on my build.