Are heatpumps the only non fossil fuel option to heat your house?

zg3409

Typically heat pumps may be more expensive to run when compared to mains gas prices back when mains gas was cheaper. I am not sure on the sums today.

Ideally heat pumps need underfloor heating to maximize efficiency but if you are increasing insulation massively at the time then the old radiators may work if run luke warm 24/7/365.

Ideally you want good controls and zones to ensure bedrooms are cooler and house is correct temperature as heat pumps can take hours or days.m to ramp up and down unless heating has been left on.

As suggested if house is passive (lots of south facing windows) then it may need little energy input and any source of heating such as cooking may be enough to keep house warm. Typically passive houses will have a small heat source such as a pellet stove or electric or heat pump. If you have mechanical forced ventilation with heat recovery that can have 'inefficient' electric heater but if house is passive the cost won't matter.

The main 3 things are insulate, insulate, insulate.

graememk

What are peoples gas use over the winter months (in kWh) out of curiosity.

If that was divided by 3.5 and multiplied by your electric rate would give a rough heatpump running cost, if one was to go down that road.

My current scop is 3.36, but that a flow temperature of 50ish c and also heating DHW, on an "inefficient" cylinder. I haven't got around to replacing that yet. Also haven't split out my logging to separate space heating and DHW.

Its replaced a 40yr old oil boiler, and drastically reduced my turf useage. (Practically none since end of January) It is run on night rate/batteries/solar, so my unit cost is less than the average.

Getting the cavity wall pumped is on the to do list too. Only replaced 1 rad so far in our living room for a bigger one, it does have 2 big windows and 2 external walls so there is more heat loss in that room too.

Also a stove which drives up the air changes too. Although the pm2.5 meter I have in the room sits at 1-5 most of the time unless I burn something in the kitchen!

Lewis_Benson

Firewood.

loyatemu

https://www.boards.ie/discussion/comment/122006431#Comment_122006431

that formula only applies if your house is already well-insulated. Most people would need to improve insulation to install a heatpump so their total kWh should reduce. If I just replaced my gas boiler with a heatpump the house would never get warm enough in winter.

Shoog

My point of view is that if you get to the stage where a heat pump makes sense then a simple stand alone pellet stove makes far more sense at about a 5th of the cost.

graememk

https://www.boards.ie/discussion/comment/122008969#Comment_122008969

Humour me, what is your gas boiler set at? Is it a condensing one?

If it is condensing, have you tried running it at a lower flow temperature to see what happens and allow it to be in condensing mode longer? The lower you can get the return temperature the more efficiency you can get out of the gas.

loyatemu

I think I have it set to 65 (having previously lowered it) but I don't think if I set it to say 50 it would be sufficient to heat my leaky sieve of a house. But it's possibly an experiment worth doing.

graememk

https://www.boards.ie/discussion/comment/122009121#Comment_122009121

Yeah it's an easy experiment. And easy to reverse.

If your radiators are single panel, swapping them to double could allow lower flow temperatures. Firefly have charts for their radiators,

(numbers from the sky here)

But say a single panel outputs 1kW at 70c(delta 50, difference between room temperature and flow temperature)

And the double has an output of 2kw at delta50

It may have a 1kw output at delta30 same amount of heat at lower flow

loyatemu

though as we use the gas for water heating as well, there's a limit to how low I can go as it will reduce the amount of water available for showers.

ixoy

https://www.boards.ie/discussion/comment/121984124#Comment_121984124

New windows/doors + external insulation might not be enough (unless you've already checked). For me, to get the relevant HLI (and therefore a grant), I'll need underfloor insulation and new radiators. Underfloor insulation is very disruptive - you'd have to move out of the house, have floors ripped up, etc. Worth checking this out and it's something I have to consider if I replace my existing gas boiler with a heat pump. I can't see it ever paying itself back (new flooring alone, never mind the heat pump cost even with grants) so it'd be entirely a question of comfort.

windowcills

I find it very streasful to read all the bickering that goes on over oil vs gas vs heat pump vs turf

But what always makes me laugh is when posters point out that a heat pump works really well in an air tight & well insulated house, as if this is a new scientific breaktrough

There was attic insulation in my house 50+ years ago, and a snake thing under the front door to keep out draughts so were my parents getting ready for heat pumps to be invented??

Shoog

https://www.boards.ie/discussion/comment/122009312#Comment_122009312

The level of retrofit needed to justify a heat pump is so much further on than you are describing that it's like comparing a Ford Focus to a space rocket. Every single detail at every single opening and transition needs to be addressed - people need to understand this before ever contemplating installing a heat pump.

DC999

https://www.boards.ie/discussion/comment/122009229#Comment_122009229

Plus 1 to that. I’ve run an ‘experiment’ in my house for the last 2 winters. A 1.5kW oil-filled electric rad has heated our 5 x 5m room sitting room + kitchen in a very leaky house with single glaze windows and no insulation.

That tells me we are heatpump ready without retrofits bar maybe a larger rad for comfort.

We're all saying the same thing I feel - that a heating bill will be larger in a leaky house, irrespective of what type of fuel and heating system we use

unkel

https://www.boards.ie/discussion/comment/122009331#Comment_122009331

I used to think that, but it is mostly a misconception. It is all about sizing the system correctly. It depends of course on the cost of gas/oil vs. electricity and how much the install of the heatpump costs (net to you).

All that said, some people have installed a system themselves, bought the pump at a good price, have cheap night rate electricity / a large battery and lots of PV. Then it starts making a lot of sense

In my own case - not heatpump related - I switched off my gas boiler end of March and I have been heating my house and water exclusively with COP 1 electricity: immersion for hot water and crypto mining rigs for home heating, both running on 5c night rate, directly or via battery

ColemanY2K

https://www.boards.ie/discussion/comment/122009312#Comment_122009312

a bit of an odd post. i went back to read the thread, all i can see is healthy debate and helpful advice being dished out.

Shoog

https://www.boards.ie/discussion/comment/122009826#Comment_122009826

Thats fairly involved system to be doing what you are doing - far more involved than most people retrofits. If most people were dependent on night rate they would repeating the horrors of storage heaters - hot in the morning and cold in the evening.

Slap a heat pump in most house and it would be a receipt for significant bill increases.

unkel

https://www.boards.ie/discussion/comment/122010090#Comment_122010090

It would if you "slap" one in for sure 😂

If carefully calculated and executed, an air to water heatpump system should get high efficiency even in a leaky old home. For me the initial cost of a professional install are simply way too high. Compared to what I run now, so I can't see myself installing A2W. I will likely go A2A though to replace my gas boiler. But that would be a non-subsidy install through a mate in the trade. And I'm not in a hurry as I use relatively little gas and I have access to supercheap unlimited 5c electricity