Swapping Combi for Heat Pump - Will I need a hot water cylinder?

PeterTom2777

I live in a small bungalow with a recently installed heating system made up of a combi gas boiler, new rads and pipe work.

I want to swap to a heat pump and move away from gas but have a couple of questions.

1. Will I need to install a hot water cylinder?
   My current combi boiler allows the taps and showers to have instant hot water. There is no hot water cylinder required and I would not have room for one.
   
2. Will the new rads suffice for a heat pump?
   In general would it be thought that new major brand rads would be universal for both heat pump systems and combi boiler systems?
   
   Of if anyone has any general advice please on swapping out a brand new gas boiler for a heat pump thank you.
   

graememk

1. Yes you'll need a cylinder, unless you keep the gas for the domestic hot water.
2. Maybe, it's not the brand of radiator that matters it's the size. If the size was increased and the heating system was designed to run at a lower flow temperature, doing a swap out should be fairly straightforward

But you've got a brand new gas boiler now, Unless you have money to burn, stick with the gas for now.

Unless your house is highly insulated you are likely to see a significant jump in your heating bills. Also radiators are suboptimal for a heat pump, they can work but they will further increase running costs since heat pumps work at low temps suited to underfloor heating and rads work at high temps which a heat pump will struggle to achieve.

I wouldn't.

loyatemu

Your heating system needs to be designed for a heatpump, you can't just swap out the boiler and leave everything else the same.

graememk

https://www.boards.ie/discussion/comment/121972888#Comment_121972888

Insulation has nothing to do with running cost when comparing heat sources.

Heat pumps are just a heat source.

As long as the system is designed correctly, it will get the efficiency needed to be cheaper than gas. It may mean much bigger radiators. But radiators are fine with heatpumps.

Gas also needs to be designed correctly. If it's running at 70c it won't be condensing and losing efficiency.

But I wouldn't rip out a brand new gas boiler for a heatpump to save money.

PeterTom2777

Thanks all.

The property has been recently renovated and is fully insulated, new windows, doors etc with a B1 rating. No solar or underfloor heating.

The swap for me is not a cost saving exercise as such. My main concern was the rads and having to install a large cylinder for hot water.

Would the next step be to have a technical assessment carried out? I was hoping to go with the installation offer from Bord Gais

PeterTom2777

https://www.boards.ie/discussion/comment/121972888#Comment_121972888

Thanks, house is fully insulated. Do most properties not have underfloor heating on the ground floor and radiators upstairs?

Edit: meant to say "most new properties". Looking at the new builds section on Daft appears to show heat pumps with rads on upper floors.

graememk

A lot just have radiators. Not sure when the full switch to underfloor happened.

circadian

If you got new rads they could be low temp aluminum type. I replaced all my rads during a retrofit for a heat pump and it works grand, I would say the efficiency would be better had I replaced the plumbing with the right size but I wasn't in a position to do that extra work.

You have a brand new boilers though and it seems like a waste to make the change now, the new boilers are generally quite efficient.

Heroditas

https://www.boards.ie/discussion/comment/121975300#Comment_121975300

Sure give them a shout. They should be able to advise you what is needed to get the heat pump installed and whether the existing rads are suitable.

Unless you have large amounts of surplus solar electricity it's unlikely a move to a heat pump will either save money or save emissions for the foreseeable future.