Oil+solar panel vs Heat Pump

Monfreid

Hello,
I've been granted planning permission and I'm now in the process of choosing the type of heating system that I will use in the house. I met with an energy consultant and I had the feeling that the heat pumps (air to water) and underfloor heating were the things to choose ...
Some people would say it's great some don't because it's too new or whatever (break down, not easy to get serviced, still needs electricity all the time) and would prefer oil and pv because you know what you get.
May I have your opinion, experience on this (oil heat pump)?
Thank you

First thing to do is remember that the method of generating the heat is different from the method of transferring the heat into the house, the reason I say is that so many people seem to think that heat pumps and underfloor heating are part of the same system.

The key is the type of cylinder that you use, choose one that can best take the heat source that you choose and transfer the energy most efficiently to the heating system in the house. The cylinder in fact acts as a buffer/heat store between the heat source and the heat distribution system.

Get this right and everything else works well.

Condenser

Deleted User wrote: »

First thing to do is remember that the method of generating the heat is different from the method of transferring the heat into the house, the reason I say is that so many people seem to think that heat pumps and underfloor heating are part of the same system.

The key is the type of cylinder that you use, choose one that can best take the heat source that you choose and transfer the energy most efficiently to the heating system in the house. The cylinder in fact acts as a buffer/heat store between the heat source and the heat distribution system.

Get this right and everything else works well.

This information is not even close to being true.


For one thing if you use a heat pump the hot water and heating water must be kept separately using the same water is the most inefficient way to run a system because they require two complete separate temperatures.
Buffer tanks can actually add inefficiencies to a system because they take away from weather compensation and their very presence means the introduction of more circulating pumps.
Thirdly the tank has no influence on the efficiency of the system other than to ensure full flow through the heat emitter at all times, and the storage energy they provide is negligible unless they are thousands of litres in size.

Monfreid

Thanks for the info.
I think air to water heat pump and radiators are a good option, I'm too keen on under floor heating and it's more expensive (insulation, ...)
I'm waiting for the report of the energy consultant to see what's recommended for my house (he will give me 3 options). Geothermic seems to be very expensive though.
Hard to know, so many different options ...

crazy_kenny

If I was building I would build a passive house or as close to passive as the budget allows. Stick in oil as back up and solar panels.

Monfreid

Unfortunately, I don't have a big budget for this house so I will have to pick the best heating system / insulation that I can afford, I can't go over budget for this.

crazy_kenny

Monfreid wrote:

Unfortunately, I don't have a big budget for this house so I will have to pick the best heating system / insulation that I can afford, I can't go over budget for this.

I bought a house in 2013. The house was built in 2009 but never lived in. The insulation is 100mm xtratherm in the walls and upstairs in dormer is cheap wool insulation. The house is 2200 sq ft and we find it cozy, heating it with oil boiler (grant vortex are the best) and solid fuel stove. I intend to apply spray foam upstairs in a few years.

Also make sure architect orientates the house properly to use sun to heat rooms throughout the year.

Monfreid

Thanks for the info

I'm tempted to go with Oil and Solar Panel because I know what I'll get. I'm kind of suspicious of the heat pumps being the best thing to heat a house because I can see a lot of posts from people saying that it's much moe expensive than previously "calculated" and based of their ESB bills, it sounds much more expensive than Oil ...

Condenser

Monfreid wrote: »

Thanks for the info

I'm tempted to go with Oil and Solar Panel because I know what I'll get. I'm kind of suspicious of the heat pumps being the best thing to heat a house because I can see a lot of posts from people saying that it's much moe expensive than previously "calculated" and based of their ESB bills, it sounds much more expensive than Oil ...

Heating with a heat pump will be far cheaper than heating with oil once its installed correctly. If you're thinking of installing a heat pump with radiators forget about it as you're instantly handicapping the system. I'd find some other way to heat your house other than a HP if this is the case.

Doorcase

I live in country side where i will have access to peat for free so i am very temped to go oil with solid fuel stove with back burner and solar. Will this get me past part L...why would i put in air to water and pay ESB when i have access to free peat and prob spent 300 on oil. House will be insulated to spec. Got planning so at stage where i have to make up my mind...Any advice welcome thanks..PM or public

Ke1

Just reopening this thread if I can get help at all. If all systems (air to water/oil/solar panels/solid fuel) installed perfectly what is the most cost effective? Is it cheaper to run a 2,200sq ft house on solar panels oil & solid fuel or install the air to water & pay esb? Any info would be greatly appreciated.

Ke1

Doorcase wrote: »

I live in country side where i will have access to peat for free so i am very temped to go oil with solid fuel stove with back burner and solar. Will this get me past part L...why would i put in air to water and pay ESB when i have access to free peat and prob spent 300 on oil. House will be insulated to spec. Got planning so at stage where i have to make up my mind...Any advice welcome thanks..PM or public

Just wondering how you have been getting on with expense? Did you go for the solar & solid fuel in the end?

sydthebeat

Ke1 wrote: »

Just reopening this thread if I can get help at all. If all systems (air to water/oil/solar panels/solid fuel) installed perfectly what is the most cost effective? Is it cheaper to run a 2,200sq ft house on solar panels oil & solid fuel or install the air to water & pay esb? Any info would be greatly appreciated.

the whole theory of modern building is to reduce your heat demand down so low that you dont actually need to install a high level, expensive heating system.

obviously it will cost a lot more to install a heat pump and the emmitters that work best with it, ie underfloor heating, than an oil and rad system.

so on running costs, the heat pump would work out better... but you need to include the higher initial costs an maintenance costs into your calculations.

Ke1

sydthebeat wrote: »

the whole theory of modern building is to reduce your heat demand down so low that you dont actually need to install a high level, expensive heating system.

obviously it will cost a lot more to install a heat pump and the emmitters that work best with it, ie underfloor heating, than an oil and rad system.

so on running costs, the heat pump would work out better... but you need to include the higher initial costs an maintenance costs into your calculations.

I was quoted over €20k for the air to water system to be installed but then overtime would it be more cost effective? So hard to know.

Ray Donovan

Ke1 wrote: »

I was quoted over €20k for the air to water system to be installed but then overtime would it be more cost effective? So hard to know.

Installing A2W pump, UFH and HRV in my 2600 sq ft house. Supply & install for €18,500 so yes it is an expensive initial outlay but should work out financially viable over time. Fingers crossed!!

BryanF

Ke1 wrote: »

I was quoted over €20k for the air to water system to be installed but then overtime would it be more cost effective? So hard to know.

What is your houses kWh/m2/yr ?

If you don't know what that is, ask your BER assessor or better your passive house designer..

quentingargan

I just installed an air to air heat pump in our workshop and am considering whether this would work in my house, relying on MHRV to circulate the heat. That would allow me to use just two units in common areas. Anyone else tried this? Air to air has a good COP and the installed cost was just €1750 (for a small one).

The only downside for a new house is the penalty in DEAP for heating water with electricity. A 2kw to 2.5kw PV system could provide some electricity to the house and heat water with the surplus and would have a hardware cost of about €2.5 to €3K. I think that should offset the hot water penalty in DEAP.

air

You could install a multi-split unit in your house Quentin, these comprise single outdoor unit with multiple (usually 2-4) indoor units which can work individually or concurrently. Indoor units nowadays can take the form of ceiling cassettes, radiator style fan units or concealed ceiling units.

quentingargan

air wrote: »

You could install a multi-split unit in your house Quentin, these comprise single outdoor unit with multiple (usually 2-4) indoor units which can work individually or concurrently. Indoor units nowadays can take the form of ceiling cassettes, radiator style fan units or concealed ceiling units.

Thanks, yes - but in my case the house is finished and has a grass roof, so no loft or access unless I put visible ducts. I would either have to rely on the MHRV to move the heat around the house. I wonder if I could use it to warm the air coming out of the MHRV in some way.

air

Where do the ducts run? If they are accessible could you not run refrigerant lines along the same route?
An MHRV unit won't shift enough air to distribute a great amount of heat really.

quentingargan

air wrote: »

Where do the ducts run? If they are accessible could you not run refrigerant lines along the same route?
An MHRV unit won't shift enough air to distribute a great amount of heat really.

The ducts were put in during construction, but once the ceilings were slabbed, that was that pretty much. I have a solid fuel range that heats the house (and I've 140 acres of forestry) so it isn't to save money. Maybe the less is not to be getting lazy.

gooner99

I think the air to air are more popular in mainland Europe, don't seem to be at all popular in Ireland and Uk.

On Paper it sounds like possibly a good way to heat an open plan area in a well insulated and airtight house?

glenng8

Got Quoted 13,500 for air to water mitsubishi ecodan 11Kw with 200 litre cylinder and underfloor heating (supply, install and commissioning).  Is this a reasonable price for a 2600sq ft new build?

JohnnyB23

glenng8 wrote: »

Got Quoted 13,500 for air to water mitsubishi ecodan 11Kw with 200 litre cylinder and underfloor heating (supply, install and commissioning).  Is this a reasonable price for a 2600sq ft new build?

Hi Glenng8, That sound like a pretty good price, any chance you could PM me your suppliers contact details please.

RuMan

Condenser wrote: »

Heating with a heat pump will be far cheaper than heating with oil once its installed correctly. If you're thinking of installing a heat pump with radiators forget about it as you're instantly handicapping the system. I'd find some other way to heat your house other than a HP if this is the case.

Could you expand on this ? Renovating and extending so will need new boiler. Was considering underfloor in the new build and thought heat pump was the best way to go.

If leaving rads in existing part is oil a better bet ? Is underfloor with oil an option ?

air

I'll have a go.

Heat pumps are most efficient when the difference between the heat source - the air or ground outside and the heat delivery interface - radiators, ground slab etc, is minimised.

Underfloor heating effectively creates a radiator with a huge surface area, thus it can output a lot of heat energy with a small temperature differential between itself and the air in the house.

So for example you might be able to heat a room with radiators at 60C or with an underfloor slab at 26C.

The heat pump will be far more efficient if you use the slab, as it only has to "lift" the heat from say 6C to 26C for a slab instead of 6C to 60C for radiators - assuming an outside temperature of 6C.

As you can see the temperature lift required is 2.7 times higher (54C) for radiators vs underfloor (20C).

With regard to your second query, in simple terms underfloor with oil is likely to be uneconomic. You'll have a lot of the disadvantages of underfloor (slow response, increased slab insulation requirements) with none of the efficiency gains. All your left with is the improved comfort of underfloor at a high cost.