Air to Heat Pump

ckeire · 28-01-2021 11:58am #1

Hi, We are considering getting an air to heat pump installed and also pv solar panels for electricity.
Would love to hear from anyone who has retrofitted an air to heat pump.. good points, bad points etc.. all replies would be a help to us!

mike_2009 · 28-01-2021 3:31pm

air to air or air to water?

RandRuns · 28-01-2021 3:35pm

If you are retrofitting it to an existing house get a BER done first to make sure the u values are low enough to make it worth your whie, and carry out any neccessary remedial work beforehand. One of the most common problems I hear about with heat pumps is that they are being sold to people to use in unsuitable houses. The result is an expensive mess, that is inefficient and doesn't heat your house.

ckeire · 28-01-2021 3:40pm

Air to Water. The current Ber is C2

RandRuns · 28-01-2021 3:43pm

ckeire wrote: »

Air to Water. The current Ber is C2

I wouldn't fit one to a house with a BER below B2, but someone with more expertise than me might say otherwise.

ckeire · 28-01-2021 4:57pm

Thanks for that info and advice, I will query that with the installer when getting quotes..

RandRuns · 28-01-2021 5:12pm

ckeire wrote: »

Thanks for that info and advice, I will query that with the installer when getting quotes..

Just make sure you get some independent advice. Some installers are more keen on selling a system than on delving too deeply into whether it is the right system for the client.

Calahonda52 · 28-01-2021 6:01pm

ckeire wrote: »

Thanks for that info and advice, I will query that with the installer when getting quotes..

Why a HP?
What the rest of the construction, will it be rads? new or old or UFH

The installer won't give a damn.
Any professional installer will do a heat loss calc, required anyway by SEAI if you are getting a grant.

Purgative · 28-01-2021 6:07pm

We had one fitted by SEIA about 4 or 5 years back.

Personally, I love it. The house is pleasantly warm all the time and the bills are comparable with oil. I suspect they wouldn't fit it now because the house is too old and expensive (just my opinion). We had: cavity pumped, external cladding, new windows and doors.

The PV I'm a bit meh about. Its great during the summer and I'm sure the ESB is grateful.

ZeroSum76 · 29-01-2021 6:57pm

Going for an air to air heat pump in our retrofit.

The one we are going with is a NILAN Compact P and it's an all in one unit that does ventilation, heat recovery and domestic hot water. It will be used in conjunction with Solar PV panels and we're going for a level of air tightness and windows and doors that with U Values of <0.9. We've been told that we needed to supplement it with some electric storage heaters around the house.

We recently spoke to an energy efficiency person who was perplexed that we weren't going air to water especially on a retrofit. Now am starting to freak out a little bit. Would love to hear some testemonials, good or bad on how these systems work in comparison with air to water systems and rads.

RandRuns · 29-01-2021 7:00pm

ZeroSum76 wrote: »

Going for an air to air heat pump in our retrofit.

The one we are going with is a NILAN Compact P and it's an all in one unit that does ventilation, heat recovery and domestic hot water. It will be used in conjunction with Solar PV panels and we're going for a level of air tightness and windows and doors that with U Values of <0.9. We've been told that we needed to supplement it with some electric storage heaters around the house.

We recently spoke to an energy efficiency person who was perplexed that we weren't going air to water especially on a retrofit. Now am starting to freak out a little bit. Would love to hear some testemonials, good or bad on how these systems work in comparison with air to water systems and rads.

The Nilan Compac P has a good reputation and the Irish agent is good. Surpsied by storage heaters though - are you sure they're not just radiant heaters?

ZeroSum76 · 29-01-2021 7:02pm

RandRuns wrote: »

The Nilan Compac P has a good reputation and the Irish agent is good. Surpsied by storage heaters though - are you sure they're not just radiant heaters?

OK that is really reassuring to hear. Thank you.

Apologies I may have the terminology incorrect. It's these lads:

https://rointe.ie/d-series-wifi-radiators/

Alf Veedersane · 29-01-2021 7:08pm

ZeroSum76 wrote: »

Going for an air to air heat pump in our retrofit.

The one we are going with is a NILAN Compact P and it's an all in one unit that does ventilation, heat recovery and domestic hot water. It will be used in conjunction with Solar PV panels and we're going for a level of air tightness and windows and doors that with U Values of <0.9. We've been told that we needed to supplement it with some electric storage heaters around the house.

We recently spoke to an energy efficiency person who was perplexed that we weren't going air to water especially on a retrofit. Now am starting to freak out a little bit. Would love to hear some testemonials, good or bad on how these systems work in comparison with air to water systems and rads.

That system is primarily for the ventilation with heat recovery side of things so may not necessarily provide all your space heating hence the suggestion of the supplementary electric heating.

ZeroSum76 · 29-01-2021 7:11pm

Thanks - are we crazy? It's a 5 bed circa 200sqm (post extenstion) retrofit from D2 to A1 (most likely). We are starting to panic about it now (too much lockdown time on our hands) wondering should we have gone with air to water as it's more mainstream and probably more tried and trusted. Air to air seems a leap of faith. Not to mention there is a sizeable grant for air to water and effectively nothing for air to air (when you deduct the fee of having it assessed).

Alf Veedersane · 29-01-2021 7:25pm

ZeroSum76 wrote: »

Thanks - are we crazy? It's a 5 bed circa 200sqm (post extenstion) retrofit from D2 to A1 (most likely). We are starting to panic about it now (too much lockdown time on our hands) wondering should we have gone with air to water as it's more mainstream and probably more tried and trusted. Air to air seems a leap of faith. Not to mention there is a sizeable grant for air to water and effectively nothing for air to air (when you deduct the fee of having it assessed).

A standard air to air is a lot cheaper. The system you're considering isn't an air to air heat pump. It's primary function isn't heating per se and that's why it isn't providing 100% of the space heating, the need for the electric rads.

That doesn't mean there's anything wrong with the configuration once it's designed to meet your heating needs that's what counts.

I don't know how it compares with an A2A/A2W HP + heat recovery ventilation in terms of actual performance but if you're insulating properly, your heating demand will be low anyway.

RandRuns · 29-01-2021 7:33pm

ZeroSum76 wrote: »

OK that is really reassuring to hear. Thank you.

Apologies I may have the terminology incorrect. It's these lads:

https://rointe.ie/d-series-wifi-radiators/

Yeah radiant. If there was any more than 4 in the installation I'd be looking at possible alternative systems as you are going to be reducing the efficiency of having a heat pump.

RandRuns · 29-01-2021 7:38pm

I've experience of that system in small houses and apartments - think it's a bit of a reach for your house if I'm honest.

ZeroSum76 · 29-01-2021 7:48pm

Alf Veedersane wrote: »

A standard air to air is a lot cheaper. The system you're considering isn't an air to air heat pump. It's primary function isn't heating per se and that's why it isn't providing 100% of the space heating, the need for the electric rads.

That doesn't mean there's anything wrong with the configuration once it's designed to meet your heating needs that's what counts.

I don't know how it compares with an A2A/A2W HP + heat recovery ventilation in terms of actual performance but if you're insulating properly, your heating demand will be low anyway.

We're insulating with 200mm on outside. Hopefully that will help.

ZeroSum76 · 29-01-2021 8:01pm

RandRuns wrote: »

I've experience of that system in small houses and apartments - think it's a bit of a reach for your house if I'm honest.

Oh dear. That's a worry. This thing isn't coming cheap. Is coming in at €15k on our tender/contract for Mechanical Ventilation !!

Alf Veedersane · 29-01-2021 8:10pm

RandRuns wrote: »

I've experience of that system in small houses and apartments - think it's a bit of a reach for your house if I'm honest.

Actually that's a good point seeing that it's a 200m2 house. Had skimmed over that.

Maybe the calcs show its feasible but I've seen it used in houses not quite that big but with more rads. It would possibly be the secondary heating on the BER

RandRuns · 29-01-2021 8:29pm

ZeroSum76 wrote: »

Oh dear. That's a worry. This thing isn't coming cheap. Is coming in at €15k on our tender/contract for Mechanical Ventilation !!

For what it is, that's a good price. Still think I'd be looking at other options though.

ZeroSum76 · 29-01-2021 8:36pm

RandRuns wrote: »

For what it is, that's a good price. Still think I'd be looking at other options though.

Ok thanks. Would you be looking air to water with regular rads?

RandRuns · 29-01-2021 8:39pm

ZeroSum76 wrote: »

Ok thanks. Would you be looking air to water with regular rads?

Air to water with regular or low temp rads if underfloor isn't an option.

ZeroSum76 · 29-01-2021 9:04pm

Reading back through some old emails it was suggested to us that the MHRV would meet about 70% of our heat load with the remaining 30% shortfall made up with those 500watt electric heaters dotted around the house (but not in every room). So it sounds like analysis was done on that. I say that more in hope than expectation

ZeroSum76 · 29-01-2021 9:22pm

I just looked at the prelim-BER we had done based on the spec.

I can't make head nor tail of what that says but presumably someone on here could validate. Totally understood that it's preliminary and possibly based on a bunch of assumptions.

RandRuns · 29-01-2021 9:32pm

ZeroSum76 wrote: »

Reading back through some old emails it was suggested to us that the MHRV would meet about 70% of our heat load with the remaining 30% shortfall made up with those 500watt electric heaters dotted around the house (but not in every room). So it sounds like analysis was done on that. I say that more in hope than expectation

30% of your heating load in electric rads sounds like an awful lot unless you are putting in a huge solar installation. Even then......

ZeroSum76 · 29-01-2021 10:00pm

RandRuns wrote: »

30% of your heating load in electric rads sounds like an awful lot unless you are putting in a huge solar installation. Even then......

We'll be getting a 5kWp Solar PV system & a Sonnen 9.53 with 5kWh Hybrid battery.

Daharmaster · 29-01-2021 10:04pm

I have experience in troubling shooting a similar installation that was installed to what is proposed here on a passive house installation.

The reality is the Nilan unit will cover the ventilation heat loss from the building, but not add any additional significant heat to cover fabric heat loss. The owner had a 4-5 500 W rads installed but had to add more as the house was struggling to maintain a comfortable temperature above 21C.

Realistically depending if the passivehouse is occupied or not during the day you need 15w/m2 of rad capacity installed. On a 200m2 house that’s 6-7 500W units. If not passive house standard but current building regs you’re will need more. In addition bathrooms should be running hot all the time to reduce moisture issues. This means you will end up with a significant electrical bill with a 2-3kW load continuously on in winter months. While still a lowish heating bill compared to older construction, using electric heaters like this, takes from the energy efficiency solution in my opinion.

There are not many air to water heat pumps in the 3-4kw range.

Also worth noting the Nilan unit acts as the master controller which turns the electric rads on and off by monitoring exhaust common temperature. it takes consideration how to set the operation correctly. The owner in this case was left to figure it out, and was struggling to manage the system.

Adding heat pumps and rads will add significant CAPEX on top of the Nilan unit, however consideration should be given to overheating issues in highly insulated buildings with significant southern and westerly glazing exposure without appropriate external shading. Overheating in summer is an issue in these buildings as external shading measures tend to be value engineered out. I have experience of another installation who was experiencing 35C in bedrooms at night. An underfloor heating system with a heating and cooling option on the heat pump might be warranted.

If was me and I was short of cash I would put in the electric rads, and run in underfloor heating pipes to a manifold for future connection to a heat pump, to cover heating running costs concerns and cooling concerns if it arises down the line.

Also of note underfloor heating is not recommended for people with rheumatoid arthritis issues.

ZeroSum76 · 29-01-2021 10:30pm

Daharmaster wrote: »

I have experience in troubling shooting a similar installation that was installed to what is proposed here on a passive house installation.

The reality is the Nilan unit will cover the ventilation heat loss from the building, but not add any additional significant heat to cover fabric heat loss. The owner had a 4-5 500 W rads installed but had to add more as the house was struggling to maintain a comfortable temperature above 21C.

Realistically depending if the passivehouse is occupied or not during the day you need 15w/m2 of rad capacity installed. On a 200m2 house that’s 6-7 500W units. If not passive house standard but current building regs you’re will need more. In addition bathrooms should be running hot all the time to reduce moisture issues. This means you will end up with a significant electrical bill with a 2-3kW load continuously on in winter months. While still a lowish heating bill compared to older construction, using electric heaters like this, takes from the energy efficiency solution in my opinion.

There are not many air to water heat pumps in the 3-4kw range.

Also worth noting the Nilan unit acts as the master controller which turns the electric rads on and off by monitoring exhaust common temperature. it takes consideration how to set the operation correctly. The owner in this case was left to figure it out, and was struggling to manage the system.

Adding heat pumps and rads will add significant CAPEX on top of the Nilan unit, however consideration should be given to overheating issues in highly insulated buildings with significant southern and westerly glazing exposure without appropriate external shading. Overheating in summer is an issue in these buildings as external shading measures tend to be value engineered out. I have experience of another installation who was experiencing 35C in bedrooms at night. An underfloor heating system with a heating and cooling option on the heat pump might be warranted.

If was me and I was short of cash I would put in the electric rads, and run in underfloor heating pipes to a manifold for future connection to a heat pump, to cover heating running costs concerns and cooling concerns if it arises down the line.

Also of note underfloor heating is not recommended for people with rheumatoid arthritis issues.

Huge thanks for the detail. Thanks to everyone who has chimed in this far actually. It's incredibly helpful and most appreciated.

I have serious concerns now as the original quote we got back had way more rads and it was scaled back as it was thought to be overkill. Sounds like it wouldn't be.

So now in addition to the heating concerns overheating in summer seems to be a real genuine concern. We are building an extension which is planning to have a 6m opening facing due South, with either large slider or bi fold doors. It's a complete sun trap. No real significant shading has been planned.

Sounds like we would be better off altogether ditching the Nilan Compact P idea with the electronic rads and exploring an air to water system with rads?

Another consideration is we have a suspended ground floor which is getting insulated underneath and made airtight etc so we can't really go underfloor heating route.

Daharmaster · 29-01-2021 10:43pm

Bear in mind if you ditch the Nilan unit you still have to buy an MVHR system and a DHW tank plus immersion, plus heating source. You won’t get out of that for €10-€11k wired and plumbed. The Nilan unit is a nifty solution for MVHR and DHW supply. You are paying a premium for the heat recovery for the DHW. If you have alot of females in the house with a large DHW demand it might pay for itself in 10 -15 years.

You need to decide how to heat your house.... which in my opinion is separate discussion to the installation of the Nilan Unit.

MicktheMan · 29-01-2021 10:46pm

Just wondering what stage of the build you are at and whether you would maybe consider running your design through the passive house model (PHPP) to give a much more accurate picture of heat load requirements and also overheating risk. Not cheap to have done but could save €€€ in long run.

Fyi, I also have a CompactP and find it great but in a much smaller footprint.

Air to Heat Pump

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