Air source heat pumps

Mooneen

Hi Guys,
Half way through a new build and the budget is already taking a hammering, the architect has suggested we use air source heat pums for domestic hot water as oppposed to solar panels that are on the original drawings, architect reckons we can save on capital costs, has any body used the air source heat pumps for DHW rather than heating ?

beyondpassive

Inverter Air source heat pumps can be a good solution for an ultra low energy buillds with MHRV and good airtighness, where the space heating has small lifts and low temp heating such as underfloor and towel rails. Be careful though, dosent suit badly insulated or thermally unbroken builds as the return temps are low. Also check that you can comply with the 10kWh/m2 renewable obligation with the heat pump alone.

Mooneen wrote: »

Hi Guys,
Half way through a new build and the budget is already taking a hammering, the architect has suggested we use air source heat pums for domestic hot water as oppposed to solar panels that are on the original drawings, architect reckons we can save on capital costs, has any body used the air source heat pumps for DHW rather than heating ?

Do-more

Mooneen wrote: »

architect reckons we can save on capital costs,

From that statement I can only assume that the architect means for you to use a hot tank that has an integrated 3kW air to water heat pump, otherwise I can't see how you are going to do it and save on capital outlay.

I can't remember seeing them mentioned here before but they come up quite a bit on some UK forums.

Whilst there are some European producers most of them are produced in China and normally come in either 190 or 300 litres capacities, some are supplied with a solar coil fitted which would give you the flexibility to add solar panels in the future if funds allow. Prices are between about €1600-€2750 depending on capacity and spec. they usually have an electrical consumption of 550-850W.

AFAIK these do not have any form of defrosting mechanism so rely on being fed warm air year round. Most people have them ducted to take air from inside the house year round although some have them set up to take in air from outside the house when ambient temperatures are high enough.

So if you are taking air from inside the house you are taking heat from some other source and converting it to hot water.

That may be fine if you have some area of the house which is over heated at times such as with a wood burning stove or a south facing sun room and you can duct the air from them to the tank.

But if you are heating the house with some other source which can be well controlled such as gas or oil then I don't really see this type of device making a great deal of sense, I would have though you are better to heat the water directly from that source.

You need to give us some more info OP as to what exactly the architect is proposing, a lot depends on what other heat sources you have, it is possible that they have a well thought out control strategy that makes sense for your build?

snow mad

Mooneen wrote: »

Hi Guys,
Half way through a new build and the budget is already taking a hammering, the architect has suggested we use air source heat pums for domestic hot water as oppposed to solar panels that are on the original drawings, architect reckons we can save on capital costs, has any body used the air source heat pumps for DHW rather than heating ?

i am also considering installing 1 of these systems did you go ahead with it if so is going? the company that i am in contact with will disconnect the DHW from the heating system and is claiming it will provide all DHW for around 100euro/pa does anyone have 1 of these systems if so do they think it is worth the extra investment compared to solar panels?

rosepaddy

Mooneen wrote: »

Hi Guys,
Half way through a new build and the budget is already taking a hammering, the architect has suggested we use air source heat pums for domestic hot water as oppposed to solar panels that are on the original drawings, architect reckons we can save on capital costs, has any body used the air source heat pumps for DHW rather than heating ?

we have heat pump air to water but use solar for the domestic hot water heat pumps can find it more expensive to get water to higher temperatures, if you have a heatpump doing your house anyhow ok use night rate to top up your cylinder, if you have a good demand for hot water use solar no question, do it properle you can use your solar to contribute to your heating as well, what is your primary heating source what size house underfloor or radiators

Dubfirefighter

Hi all, looking for advice. I have a wind turbine, would it be worth my while investing in a air source heat pump, and what sort of costs are involved.

Do-more

Dubfirefighter wrote: »

Hi all, looking for advice. I have a wind turbine, would it be worth my while investing in a air source heat pump, and what sort of costs are involved.

Not sure what you are getting at in terms of wanting to get an ASHP because you already have a wind turbine?

Just because you have a source of electricity doesn't necessarily mean that a heat pump is a suitable way for you to heat your house.

For want of a better way of explaining it, heat pumps can't "blast" your house with heat in the same way as an oil or gas heating system can so they are really best suited for use in well insulated houses. How well is your house insulated?

Also heat pumps are best used with low temperature heat delivery systems such as under floor heating or fan convectors. Existing radiators sized for use with oil or gas CH where the flow temperature is normally 70C will not work very well with the 45C flow temperture supplied by a heat pump.

I'm not saying that a heat pump can't be suitable for you but I am just trying to point out some of their limitations and avoid you the heart ache of spending money on something that may be totally unsuitable for you despite having a cheap source of electricity.

Lets us know about your house's insulation and airtightness and it's heat delivery system and how you currently heat it and we can then explore further whether a heat pump is the right choice for you.

HoofRocks

Hi All

In a similar situation ourselves, currently trying to decide on a main heating system for our 1650 sq ft bungalow.

Were installing HRV and will have room heating stove in sitting room and open plan kitchen living. We were nearly sold on air source heat pump. Went to self build show and was impressed by them, suppliers say they work in temperatures down to -20.

After reading a few comments on boards and not so sure about them now in our climate from users reviews. Were not going with under floor heating, using fan assisted rads instead. Supplier said heat pump would supply hot water and heating, no need for solar panels - any views on this?

any advice welcomed.

HoofRocks

Got a quotation today for air to water heat pump and underfloor heating upstairs and down stairs total floor area 234 sq mt not including Vat at 13.5% mind fully installed.

Heat Pump : €9290
Underfloor: €5149

How does that fair on todays prices? We were also thinking of having underfloor in just the living areas (open plan kitchen, living, dining and separate sitting) and have radiators in the bedrooms (2 up, 2 down, 1 bath and 1 shower room)

How would that system work or are you better to stick to one or the other?

Condenser

HoofRocks wrote: »

Got a quotation today for air to water heat pump and underfloor heating upstairs and down stairs total floor area 234 sq mt not including Vat at 13.5% mind fully installed.

Heat Pump : €9290
Underfloor: €5149

How does that fair on todays prices? We were also thinking of having underfloor in just the living areas (open plan kitchen, living, dining and separate sitting) and have radiators in the bedrooms (2 up, 2 down, 1 bath and 1 shower room)

How would that system work or are you better to stick to one or the other?

You'd almost get a ground source unit for that price with a longer lifespan and better efficiencies.



Having read it again you would get a GSHP for that price as I didn't note that the price was ex vat.

Do not mix rads and ufh if fitting a heat pump. Rads require higher temp water and therefore reduce the efficiency of the heat pump. You would also need a buffer if you go down that route as the rads have no thermal mass and will cause the HP to cycle far too frequently