Budget - Solar System or Heat Recovery Ventillation?

ShortPockets

In the process of building at the moment. If you had a budget for either a solar system or a mechanical heat recovery ventillation system which would you choose? I've read through the threads but I'm just more confused.

Am drylining the inner walls with insullation in the cavity also.
MJ standard windows and two chimneys.

Thanks.

craggel

Hi there Shortpockets.
You could try both! Look at www.sunwarm.com. I haven't seen the system in practice so can't tell you much about it but they use solar panels to heat your water and pre-heat the incoming air. I know a guy who has it in his house and reckons it works very well. Others who are in similar houses to himself don't think it works that well but he reckons they just don't know how to set it properly. Have a look at it and see what you think let us know if you do find out more about it as I'm looking at using it myself shortly for a new build also.
Rgds Craggel

CJhaughey

Speaking from the point of having both systems installed, Temovex 480 HRV and a 6.3m2 Solar Panel and 500l tank.
The HRV system is probably the biggest thing you can do towards making a house warm and dry, as long as it is properly insulated/constructed.
The HRV has a bypass which allows you to turn off the heat recovery on days that are warm and just provide ventilation.
When designing and constructing the house it is easy to install the ductwork for the HRV system in a nice unobtrusive manner, this is almost impossible to do after.
I would definately leave provision for the solar installation afterwards if necessary.

ShortPockets

ShortPockets wrote:

MJ standard windows and two chimneys.

Thanks.

I have also installed MHRV and will install solar later, but you will compromise your ventillation if you have open fireplaces as these will cause uncontrolled draughts.

Builderwoman!

SOLAR! It's so worth it. Hot water free! Better to do it now rather than later as you will need a large water storage tank. And tie it into your heating it's also worth it.

MHRV - would have liked it but would not have liked a house without at least one fire place...also cost was prohibitive.

CJhaughey

Builderwoman! wrote:

SOLAR! It's so worth it. Hot water free! Better to do it now rather than later as you will need a large water storage tank. And tie it into your heating it's also worth it.

MHRV - would have liked it but would not have liked a house without at least one fire place...also cost was prohibitive.

I can understand where you are coming from Builderwoman, it is nice watching the tank heat up to 70+ deg on a nice day however if you cost it out it is not free, the capital cost of installing a solar system will take about 15+ yrs to pay back.
MHRV is relatively cheap compared with the solar system, my HRV system was about 4800, solar 5500.

sunnysoutheast

you can still have HRV with fires - you just need to put in a "sealed" unit such as an inset stove or pellet stove - or a chimney damper

note that I'm not talking about passive or airtight houses here, I don't know much about those

we live in a house with an open chimney now - it almost seems pointless heating the house seeing the howling gale which blows up it!

we put in extra pipes to the loft for future solar and will be installing a dual-coil tank, this is something we'll probably do next year in time for summer

Builderwoman!

We were quoted over 10 grand for MHRV. We did solar for 6. I know there's a 10-15 year payback but it would have been a lot longer for us for MHRV. We did the right thing for us. It's fab not burning any fuel these days and having hot water t 24/7.

mjffey

Builderwoman! wrote:

We were quoted over 10 grand for MHRV. We did solar for 6. I know there's a 10-15 year payback but it would have been a lot longer for us for MHRV. We did the right thing for us. It's fab not burning any fuel these days and having hot water t 24/7.

10 grand? That's a lot of money. It's cheaper to open a window now and then if you want fresh air:D, and I'm convinced that it's healtier.
Our solar system will cost under 4 all in, and that's without the grand, but that's probably because we don't need a big system and only a 300l tank.

Calluna

I just had a quick question with regard MHRV and air tightness...?
Am sold on the concept of MHRV but some of the reps I have spoken to say that air tightness isn't as important, especially as we are not going for a fully passive house, etc. I'm just wondering is that telling me what I want to hear (would really like one fire place...intend to have a stove also) and if anyone has any experience in this regard.

The prices quoted for the systems are reasonable, but what would be involved in making the house air tight?
I would be quite happy to put in a chimney damper, but would prefer not to have to get specialist 'sealers' in to do other parts of the construction work, or to test for air tightedness afterwards as I'm hoping to oversee the build myself rather than go for a contractor - even so, most of the local contractors wouldn't have experience in MHRV, let alone air tight construction.

Basically I realise that the efficiency would be decreased somewhat by not having the building airtight, but I'm wondering if it's all a waste of money if I don't make it airtight....or at least more a waste of money than drilling ventillation holes in my highly insulated cavities?!

BTW we are building a concrete build, 2,800 sqft two storey. To add in to the main poster's question - I don't have any first hand experience yet (and don't even have foundations dug yet) but have lined up my solar tubes already as no. 1 priority. Am still sussing out MHRV. We're lucky though - back of house is directly south facing and so was designed with solar in mind from the outset.

bakerbhoy

Calluna wrote:

I just had a quick question with regard MHRV and air tightness...?
Am sold on the concept of MHRV but some of the reps I have spoken to say that air tightness isn't as important, especially as we are not going for a fully passive house, etc. I'm just wondering is that telling me what I want to hear (would really like one fire place...intend to have a stove also) and if anyone has any experience in this regard.

The prices quoted for the systems are reasonable, but what would be involved in making the house air tight?
I would be quite happy to put in a chimney damper, but would prefer not to have to get specialist 'sealers' in to do other parts of the construction work, or to test for air tightedness afterwards as I'm hoping to oversee the build myself rather than go for a contractor - even so, most of the local contractors wouldn't have experience in MHRV, let alone air tight construction.

Basically I realise that the efficiency would be decreased somewhat by not having the building airtight, but I'm wondering if it's all a waste of money if I don't make it airtight....or at least more a waste of money than drilling ventillation holes in my highly insulated cavities?!

BTW we are building a concrete build, 2,800 sqft two storey. To add in to the main poster's question - I don't have any first hand experience yet (and don't even have foundations dug yet) but have lined up my solar tubes already as no. 1 priority. Am still sussing out MHRV. We're lucky though - back of house is directly south facing and so was designed with solar in mind from the outset.

AFSIK a room sealed unit with external draught air supply will get you around the problem of airtightness.That is what i intend to do for the same reasons.

sunnysoutheast

in theory for HRV to work most efficiently I believe you should have the house "sealed", in practice this will be difficult or impossible to achieve unless specialists are involved and the cost/benefit will tail off

a further benefit of HRV is that of continous moisture control and extraction from ALL parts of the house, without having to use those standalone fans in bathrooms - but note that you should not connect a kitchen extract to HRV - and many come with a timed "boost" for use after showers etc.

one further consideration is that you'll need to clear it with whoever is signing off your build that they're happy with compliance to the ventilation reqts. in the building regs

I think in some parts of the world some form of mechanical ventilation is mandatory for air quality reasons

I don't think there is a choice to be made per se between Solar Water Heating v. HRV, but bear in mind solar will be an order of magnitude easier to fit after the house is completed and money is made available, and you can go part of the way by putting in the extra piping to the likely position and a suitable tank

SSE

ShortPockets

Thanks everyone for the replies.

I got a quote of 4,800 for solar after grant. MHRV quote was 6000 fully installed. I have some questioins...

Firstly, we will have an aga in the kitchen (possibly oil), I dont know if HRV will have a negative impact on the draft/ventilation for the oil cooker. the last thing I want is the smell of oil being pulled into the room and not up the chimney!

Secondly I am wondering if noise could travel along the ventillation pipework?

Thirdly, I could nearly garuntee that our standard contract built house (Block with drylining) will not be airtight so the potential gain might be lost already?

Shortpockets

tipperary

Apologies if this is not in the correct thread, or if covered previously, but how do the running costs of HRV add up. From what I understand, the units have a fan running continuously, and some units also include a heating unit. I have also heard rumours of running noise being an issue with some of the units. Also, are the units as quick as typical extractor fans at removing moist air from a shower room?

ShortPockets

Tipperary

I got a quote of 6000 for the HRV with estimated esb costs of approx 100euro per anum. I was told that I would need all the traditional bathroom and Kitchen ventilation as well.

RedLady

Hi,

We installed a HRV in our new build. We got it from proair who are based in Galway. From what I remember it cost €4400 in total. It has not been comissioned yet so I cant give any comments about it. We got an airtight house from Century homes. From any reserach that I did into HRV systems, it is fairly necessary that the house be as air tight as poissble for it to work well. We have friends that have installed and they said that it was the best thing that they ever did. We also put in solar panels.
Speak to David Mcugh in Proair. He seems to know his stuff.

My system cost approx €4.5K, not sure of running costs but €100 seems to be the ballpark figure.

I find tha system fairly quiet running (not completely silent) you have to listen carefully to hear it, was a bit noisier before I fitted the insulation in the loft.

Sound transmission, no problems between room outlet (livingroom, kitchen & bedrooms) vents, but the exhaust vents in the bathroom/en-suite & toilet were a bit like voice pipes (think WWII battle ships, "Bridge to engine room" ) only loud sounds :eek: tbh.

RedLady

RedLady wrote:

Speak to David Mcugh in Proair. He seems to know his stuff.

Our system is ProAir as well, Only been in the house a few weeks but good so far.

ShortPockets

Just rang Proair and got a quote of 7.5K!!! Think i will need to do some negotiation...

Depends on the house type, mine was a simple 180m2 bungalow.
hth

ollie30

ShortPockets wrote:

Thirdly, I could nearly garuntee that our standard contract built house (Block with drylining) will not be airtight so the potential gain might be lost already?

Shortpockets

from what i've been trying to find out about airtightness in a concrete block hse i've been told to wet plaster internall walls to the floor,use an air tight vapour check on ceilings and wrapped around any concrete 1st floors where they meet the inner block leaf bringing it up and down the wall about 50-100mm and bonded to the wall before plastering,i'm sure timer joists would be the same,use an aiatight tape around the windows,if possible an airtight electrical meter box,good windows and doors and seal the hell out of any hole for services or little cracks etc.i thionk a lot of it is quality control and probably not too late to use some if not all of these pointers.i'm sure some of the good people on this forum could give more professional tips than mine

RedLady

ShortPockets wrote:

Just rang Proair and got a quote of 7.5K!!! Think i will need to do some negotiation...

Our house is 2500 sq ft dormer.

ShortPockets

Thanks for the suggestions. I will go for solar panels anyway and hold off for a few more weeks on the hrv.

anon1

try ringing villavent.co.uk