Heat pump with radiators

Blues14

Hi in process of retro fitting house to eventually installing a heat pump air to water just wondering if anyone has run it through exiting radiator not those aluminium ones.had a few people say that my radiators should be good enough.just wondering if anyone has done it?

ec_pc

We have the traditional style radiators with a heat pump. I did want alluminium but builder thought he knew better and long story short we stuck with the non aluminium. However, they are rarely on as the house is so warm.

It's worth noting though that a heat pump does not heat the water as hot as an oil burner, so they will never be hot or scalding to the touch. They will be warm, but as I said if your house is insulated / air tight then you don't need extremely hot rads.

Blues14

Thanks for reply is your house a retro fit?and when the radiators on do they work well with the heat pump

ec_pc

House is 50% retrofit and 50% new build extension. Existing house was gutted with just 3 walls and roof left, everything refitted from scratch. I have not really had any need to use the rads really as house is too warm.

I think this winter they have been luke warm about 4 or 5 nights because thermostats didn't need to warm the house. The heat rising from UFH downstairs keeps upstairs warm ( about 20-21 degrees) You can easily use the heat pump to ensure you have hot radiators - you just need to ensure the water temperature is high enough but this can be quite heavy on electricity.

Blues14

Ok thanks for info

ted1

Do you not need bigger rads, as the heat is lower?

Blues14

I was told by a few people to see first hopefully not that why I’m asking to see if many people do it with traditional radiators

Biker1

https://www.boards.ie/discussion/comment/118562372#Comment_118562372

If your heat pump installer is competent they will be able to calculate the exact size of radiators required for each room. If you are applying for the heat pump grant this is a requirement. Doesn't matter whether they are aluminium or steel, it's the output that counts.

Sleeper12

Ted1 is correct on bigger rads as they produce much lower temperatures. General rule of thumb is double the rad size but this differs from house to house. You heat your home 24/7 during the winter months because it takes so long to reach tempeture. I don't doubt what Ep-ce says but it sounds like they have a lot of glass & skylights giving them a greenhouse effect.

Insulation is key with air to heat pumps. You need very high energy rating in whole house

ec_pc

https://www.boards.ie/discussion/comment/118563720#Comment_118563720

Yes, we have double rads through out upstairs. We do have a significant volume of glass in the living area and there are velux windows in the new bedrooms and landing. However they don't give much of a glasshouse effect in the depths of winter.

You are dead right regarding insulation, our house is heavily insulated. It was the one area we didn't pare back on costs when budgeting.

kbooax

If you actually consider every euro spent, between installation, repairs, maintenance, bills, etc, regular gas or oil central heating with no modern methods would actually work out cheaper, even over a 20 year period. Correct me if I am wrong please but I am almost sure I'm right

awec

https://www.boards.ie/discussion/comment/118713754#Comment_118713754

You are assuming that gas and oil stays the same price over the 20 years relative to the heat pump running costs, right?

Sleeper12

https://www.boards.ie/discussion/comment/118713866#Comment_118713866

No. Electricity prices will increase in the same way.

Some people will never recoup the initial outlay in their lifetimes.

People should definitely do their sums before committing to an air to water heat pump. It wont work out for most people without an A energy rated home

loyatemu

as we've seen in the last couple of months, a big increase in the price of gas will also push up the price of electricity (maybe that link will weaken as more wind is added to the overall mix and interconnectors come online, but that remains to be seen).

awec

The correlation between the increase in oil / gas and the increase in electricity costs will not remain the same over time though. In fact, current world events are likely to speed up the disconnect between these two things.

I agree you need to be careful if you have an old property that's not A rated, and you are trying to retrofit a modern system in to it. But I don't think that it's correct to make a general statement that gas / oil will work out cheaper over 20 years.

kbooax

https://www.boards.ie/discussion/comment/118713866#Comment_118713866

I am assuming that electricity will rise as well as oil. Even though it's possible to have cheaper electricity than oil overall eventually, I just don't see it happening for a long, long time. They have been saying this for about 60 years now. Electricity organisations will, in my opinion, always charge extremely high prices simply because they can and nobody has a choice, even if renewable resources become a much higher percentage of their power source.

brokenangel

Unless you are investing heavily in insulation in the retrofit you will be alarmed when you get the heat pump up and running how much electricity you will use

You could look at a hybrid heat pump which would use the heat pump to get the temp up to a certain level and if you needed a "top up" then an oil boiler/electric could kick in to bring the temp up and use the existing radiator

Or just buy a HT(High temp) heat pump. This works at a higher temp compared to the standard one, I don't know how much additional electricity it will use

Or stick with oil boiler but go for newer one which will support HVO, then hope the government gets it ass in gear and start to allow HVO more in Ireland like the UK are doing, this will bring the price down and have a renewal source for oil boilers. All Grant and Firebird bioilers shipped new will be HVO compatible

Sleeper12

There is a lot of misinformation about heat pumps. They can produce 4kw of energy & only use 1kw. What they don't tell you is you will get 4kw when the outside temperature is 15 or 16C. Personally I don't run my heating when it's that mild out. The 4kw to 1kw ratio drops as the outdoor temperature drops. Very few people will be getting 4 to 1 on an air to water system & they will see that ratio drop to 1kw to 1kw in cold weather. Ground to water is a different kettle of fish but costs are very high for installation. Unlike gas & oil the heat pump can't heat the water in the rads or the hot water cylinder to a high temperature. Your hot water cylinder will need to be topped up with an electric immersion. For the rads you need to heat twice as much water because of the bigger rads required . For air to water systems you usually leave heat on 24/7 because it takes so lone to heat up. Just taking the rad size alone. Double size means double the amount of water heated compared to oil or gas. So now a 2kw to 1kw ratio in cold weather heating twice as much water effectively gives a 1kw to 1kw. A KW of electricity costs 3 times more than a kw of gas.

I don't believe anyone will save enough to cover the outlay of the heat pump in 20 or 30 years. There are positive things to it though. You will have to bring the insulation standard of the home up close to A rating. The comfort level of your home increases too. You will help save the planet. You will have air conditioning for the summer months. You wont save money though

awec

https://www.boards.ie/discussion/comment/118714470#Comment_118714470

Even aside from the inevitable rise in production costs of oil / gas, you can be absolutely certain though that governments will start to impose serious punitive taxes on fossil fuels so it will be a double whammy.

I think current events are going to focus minds on this and you will see a renewed focus on weaning everyone off oil and gas. The days of cheap oil and cheap gas are coming to an end.

My own house is gas. If I was building a house now, or buying a new one, it would be a no brainer to go for something like a heat pump. If I was retrofitting I'd need to look at the sums, but you would have to factor in that running a boiler is going to get a lot more expensive in future.

brokenangel

https://www.boards.ie/discussion/comment/118714686#Comment_118714686

We cannot be certain of that, if HVO got pushed into the market this could* stable the market and give people with oil boilers a way out of trying to do very expensive upgrade to make a house heat pump ready.

Purgative

https://www.boards.ie/discussion/2058230522/heat-pump-with-radiators

Yeah we have. Works fine. Been in about 6 years. House is always pleasantly warm.

The radiators never get so hot like with an oil boiler but its fine. We have a stove for chilly evenings. Works well and I wouldn't want to go back to oil or solid fuel.

GreeBo

https://www.boards.ie/discussion/comment/118713754#Comment_118713754

You could also just have a cold house and water and save thousands. :)

A modern, insulated house is far more comfortable to live in than the alternative, so you cant just look at the costs in isolation.

Sleeper12

I have to agree with GreeBO. Comfort levels are where it's at. 9C outside right now. No heating on since 8am & my sitting room is 20c, kitchen 21c. The coldest tempeture in any room in my home this winter was 14.5C. This was 5am, frosty outside & no heating on for the last 7 or 8 hours. Insulation is the most important thing in your home. I've seen people spend 1000s, on solar, pv solar, heat pumps etc & not spend on insulation. The biggest return on your money is insulation

kbooax

https://www.boards.ie/discussion/comment/118726271#Comment_118726271

What? I'm talking about the price to make it comfortable temperature. Why would you have a cold house or water if your central heating on half the day? My point was that it will cost you more for a heat pump, if you consider everything, to have your house at a comfortable temperature if you are retrofitting, which is what this original post is about. Completely different story if your house was built after 2015.

kbooax

https://www.boards.ie/discussion/comment/118726513#Comment_118726513

I agree, adding insulation makes a massive difference, especially with older houses. Can I ask what U rating windows you have and if they are triple glazed? I would imagine there are circumstances where upgrading windows and doors would be far more worthwhile than installing a heat pump.

Sleeper12

I'm double glazed. I've no idea what the U value might be. They are 10 years old.

_Brian

Our home already has a hybrid heating system with a high efficiency oil burner and back boiler stove heating conventional radiators, high levels of insulation.

i would consider adding a heat pump as a third option but not sure.

when we were building opting for a heat pump system was an ADDITIONAL €27k onto the price of our current system and the figures just didn’t add up.

brokenangel

https://www.boards.ie/discussion/comment/118735642#Comment_118735642

We have the same, plan was to remove the back boiler stove and replace with a A2W. Then we priced and got told it would be 20k. Will buy a lot of oil to make that worthwhile

karltimber

I live in a 1970's cavity block built house, with dabbed on plasterboard on all external walls. Oil heating. House cools very quickly when heating is turned off. Open fire has a back boiler so that keeps the house temp topped up in the evenings.

Built a single level extension side & back with cavity wall & insulated plasterboard 10 years ago. that helped downstairs.

Plan is to put on 60mm insulated pb on all upstairs ext walls, insulate between joists under floor boards, and properly insulate the attics of both house and extension. Get rid of the open fire for a stove. might get extension cavity wall pumped (even though it has insulation in it). Upgrade windows & external doors too.

Will get some money for the upgrade but will do most of the upstairs work myself. Pity they can't give some type of grant for diy upgrades (with checks).

Heat pump would not work due to age of house. Hopefully the insulation upgrades will reduce oil usage considerably.

K

jim-mcdee

https://www.boards.ie/discussion/comment/118714679#Comment_118714679

Can the radiators act as an air conditioner or is there an extra thing needed?

Sleeper12

https://www.boards.ie/discussion/comment/118761305#Comment_118761305

There are dual air to water heat pumps for heat & air conditioning. They are called Air/ water split heat pumps

Was chatting to a guy today who is doing them.

He has solar and most of the power is coming from his panels.

He said 16000e minus a grant of 6k.

C. Eastwood

Kbooax

i agree with you

it would be cheaper to seal the holes in the ceiling:- around pipes in the ceiling of the hot press; around the wires above the Fuse Board; around the wires of the all ceiling light fittings and draught proof the Attic access door

plus you don’t have your home as a building site- no stress

no bank loans

no incompetent morans damaging your house.

Many people are having their home externally wrapped in insulation (advised by Top Insulation Experts) and all of the warm air will still flow through the inner concrete block leaf, and when it reaches the cavity, the warm air must rise up and will escape through the open cavity in the gable walls. €25,000 paid out; brilliant updated BRE Cert; everyone happy; and the heat loss is the same as before the fitting of the new external insulation. (Please keep this a secret between us) 😂😂. External Insulation wondering when the feck is the heat is going to come out to meet me.

At least the house won’t overheat in Summer in our 27 degrees.

no damage to your house- some houses after having the cavity pumped-with the incompetent plaster/dashing patching- the house looks like it has the measles.

Have a super holiday instead.

we live in Ireland with -1 degree, 1 or 2 days a year.

Fr Jack was correct. Drink, Feck, Girls.😂😂😂

C. Eastwood

Kbooax

i agree with you 

it would be cheaper to seal the holes in the ceiling:- around pipes in the ceiling of the hot press; around the wires above the Fuse Board; around the wires of the all ceiling light fittings and draught proof the Attic access door 

plus you don’t have your home as a building site- no stress 

no bank loans 

no incompetent morans damaging your house. 

Many people are having their home externally wrapped in insulation (advised by Top Insulation Experts) and all of the warm air will still flow through the inner concrete block leaf, and when it reaches the cavity, the warm air must rise up and will escape through the open cavity in the gable walls. €25,000 paid out; brilliant updated BRE Cert; everyone happy; and the heat loss is the same as before the fitting of the new external insulation. (Please keep this a secret between us) 😂😂. External Insulation wondering when the feck is the heat is going to come out to meet me. 

At least the house won’t overheat in Summer in our 27 degrees. 

no damage to your house- some houses after having the cavity pumped-with the incompetent plaster/dashing patching- the house looks like it has the measles. 

Have a super holiday instead. 

we live in Ireland with -1 degree, 1 or 2 days a year. 

Fr Jack was correct. Drink, Feck, Girls.😂😂😂

iColdFusion

https://www.boards.ie/discussion/comment/118714686#Comment_118714686

If you had an existing oil or gas system it would be quite hard to justify changing to a heat pump, the main saving in a new build is to not have to buy and install an oil tank or pay for a natural gas connection, you are already getting an ESB connection anyway.

The thing not mentioned here is you can run a heat pump on night rate electricity and get some help from PV panels during the day, its not set in stone what that night rate will look like in the future but there is no such thing as night rate gas or oil and you can't generate it yourself.

More likely night rate will disappear and we will have smart grids with your smart ESB meter talking to your heat pump and electric car telling them to work when there is excess capacity in the grid, night rate isn't really ideal for heat pumps as air temps are the lowest anyway.

On the topic of heat pump with rads, underfloor heating is better for heat pumps, you run it over night on cheap rate to preheat your floors which release the heat throughout the day, rads don't work as well at this as they give out the heat much sooner.

This is all pretty moot though, oil boilers officially banned in new homes this year and gas boilers in 2025 although both effectively gone for a few years as harder to meet current Part L energy regs with them.

MicktheMan

https://www.boards.ie/discussion/comment/118761248#Comment_118761248

"I live in a 1970's cavity block built house, with dabbed on plasterboard on all external walls. Oil heating. House cools very quickly when heating is turned off."

The level / type of insulation in your walls / roofs is not the real issue here. It's your airtightness (or the lack of) and I fear that the works you have planned may do little to reduce your oil consumption or you may well be disappointed with the outcome.

Perhaps before starting on any "upgrades", have the house tested for its primary heat loss mechanism and invest wisely thereafter.