Heat Pump alternatives

bullpost

I've been following the recent trend to push houses to switch to Heat pump systems as a "green" replacement for current fossil-fuel central heating choices such as gas boilers.

Seems to me the cost of these new systems will be prohibitive and uneconomic to a lot of people , me included.

So I've trying to check out acceptable alternatives.

I've been looking at electric Combi boilers as being a cheaper replacement for my gas boiler when it goes - sometime in next five years I'd guess.

From what I'm reading they may not be as cheap or as efficient as a gas boiler to run, but my house is pretty well insulated anyway and I dont need to have heating on constantly except for very cold winter nights .

Am I right in thinking this approach will be better for me than a Heat pump while still letting me conform to the new greener choices for my home?

Sleeper12

Electric combi boiler will be a lot more expensive to run than your gas boiler. They are very efficient as in there is almost no wastage but your heating bill will double or more. At the end of the day it is electric heating. Heat pump will work out far cheaper in the long run. The combi boiler may be 100% efficient but the heat pump can be 400% efficient. The Heat pump can produce up to 4 times the amount of energy than it uses.

cruizer101

One of the main issues with heat pumps is the push to use them in all houses, many houses just aren't suitable, you need a certain level of insulation that can be hard to achieve in older properties.

One potential option are combined units which have both a heat pump and oil/gas boiler, these can be good as you get best of both worlds however you I think they are an expensive option.

One option I am vaguely considering is A/C split units which also work as Air to Air heat pump combined with traditional boiler. So in cooler weather you use the heat pump to heat and it will work fine but when it gets proper cold you have the boiler to kick in as the heat pump wouldn't cope with the full heating demand on colder days.

Something like this is only 1500, obviously install cost also but would be far cheaper than a A2W Heat pump. COP won't be as good as with A2W but is still decent enough.

bullpost

https://www.boards.ie/discussion/comment/118089913#Comment_118089913

Yep I get they more efficient but my issue is the upfront investment. In my case , with very low heating bills anyway, and plans to probably move house sometime in the next ten years, I'd never recoup my investment.

Furze99

There's sure a lot of marketeering and churning at the moment and increasing. It's a time of change, some solutions & technologies will work and others one suspects will be found to be wanting and quietly discontinued once their promoters have made a few bob out of them. Very hard for the ordinary citizen to figure what is the best long term cost effective and durable solution. Maybe buy a few woolly jumpers and a housecoat would be the wisest!

thebourke

how much does a heat pump cost?

bullpost

https://www.boards.ie/discussion/comment/118090162#Comment_118090162

Yep - Thats where I'm at. For me I was thinking even if a few Dysons heaters scattered around the house, couple with my immersion heater would work out far cheaper while waiting for the gurus to come up with something thats more realistic for vast majority of us who dont have €15,000 or thereabouts stuffed down the couch 😀

bullpost

https://www.boards.ie/discussion/comment/118090164#Comment_118090164

Besides the cost of the Pump itself, most houses will need considerable additional investment to make the dwelling suitable for a heat pump. This will involve substantial insulation, potential replacing of radiators and plumbing to make it feasible for the house to heat efficiently with the lower constant heat emitted . I've seen an average cost pegged at €15,000.

thebourke

how much doe the seai grants to work out at?

Sleeper12

https://www.boards.ie/discussion/comment/118090036#Comment_118090036

Put in another gas boiler. Best option if moving in 10 years or so

Ubbquittious

I'd throw in a decent size back boiler stove, as long as I was able to get the logs

bullpost

https://www.boards.ie/discussion/comment/118093732#Comment_118093732

Well I want to put something in thats "green", which is why I am looking at the electric boiler. I suspect anything based on fossil fuels will get more and more expensive going forward.

Ubbquittious

https://www.boards.ie/discussion/comment/118102585#Comment_118102585

There are not that many options available that are renewable. You either get a heat pump which is expensive and has all the heatpump problems or burn wood

I've been in one house that has a resistive heating element instead of heatpump but that is ferociously expensive to run. Definitely would not recommend

If you have an absolutely massive underground storage tank + lots of solar thermal panels then solar heating might be possible but its an exotic solution and don't know anyone who uses it or how well it would work.

bullpost

https://www.boards.ie/discussion/comment/118102832#Comment_118102832

Thanks for that and it does look to be that way currently. I will probably delve deeper into electric Combi boilers to get better idea of running costs and figure out if I'll need to make any changes to my existing central heating system to accommodate.

autumnalcore

Natural gas in a combi boiler is about 3-3.5 times cheaper than Electricity per kwh

Thats if you change companies every year

If you stay with the same company electricity can be 4-5 times the price of gas.

Seai do a price comparison and update it a couple of times per year

https://www.seai.ie/publications/Domestic-Fuel-Cost-Comparison.pdf

Average irish household uses 11,000kwh per annum in gas.

Electric ireland doing 4.66 cent at the moment for gas including VAT

11,000kwh * 4.66cent = €500

Cheapest 24hour rate at the moment is around 16.08c per kwh for electricity

11,000kwh * 0.9 (efficiency of combi boiler is lower than electricity) * 16.08 = €1768

Depending on usage a night meter might reduce costs a little.

Note if you have a bungalow an air to air heat pump system can be a fraction of the cost of air to water.

autumnalcore

oops forgot to multiply by the 0.9

11,000kwh * 0.9 (efficiency of combi boiler is lower than electricity) * 16.08 = €1591.92

Bear in mind 11k kwh is an average yours could be way higher depending on house construction, windows, floor area, exposed location etc.

Calculations ignore standing charges if getting rid of gas entirely then the standing charge for gas can count towards electricity ~ €120

mike_2009

Yep was thinking A2A for space heating and point of use electric heating for water - boiling water tap for kitchen, electric showers and instant water heaters for other outlets - no hot water tank or at least not one that's heated anymore. Might need power cable upgrades and priority switches to avoid overloading the consumer board though. If you're moving in 10 years consider getting a battery and inverter and take it with you - get nightsaver and charge overnight and use during the day. Keep investment. Get 1/2 price leccy too for all that stuff. Load up space heating overnight and top up during the day in winter.

Note that BER will NOT like instant water heaters and could be a sellers hurdle in 10 years.

Sleeper12

https://www.boards.ie/discussion/comment/118102585#Comment_118102585

The problem is the 10 years timetable you have. Whoever buys your home in 10 years will rip out the uneconomical electric combi boiler. To be truly green you have to look at the bigger picture.

The combi boiler mightnt even help much with the BER rating because they are so expensive to run and the amount of energy they consume.

bullpost

https://www.boards.ie/discussion/comment/118103829#Comment_118103829

I dont have figures to hand but my thinking is based on fact that the house is very well-insulated and mostly triple-glazed. Yesterday was a cold dark day but we hardly had heating on during day and just periodically during the night downstairs. Our bills are small so hence my worry about something like a €15000 investment up-front. It would take me longer than I will live to recoup that 😆

antoinolachtnai

An electric boiler isn't a 'green' choice. For every kWh of heat delivered, the electricity system will need around 1.3 or 1.4 kWh of fossil fuels. (because 70 percent of the electricity is from fossil fuels and every kWh of electricity from fossil fuel is going to need 2kWh of gas to generate it. The efficiency of gas plants is that bad. You also need to factor in a loss factor on the electricity network of around 10 percent.)

So your electric boiler will use more fossil fuels than your gas one. This will change as the amount of renewables on the grid increases, but don't expect this to reach 70 percent until 2030.

A heat pump is a 'green' choice because it is a heat pump, not because it runs on electricity.

You could run the gas boiler you have (if you have one) until it dies, then put in an air-to-air heat pump to heat the downstairs and some panel heaters in bedrooms upstairs.

bullpost

https://www.boards.ie/discussion/comment/118107773#Comment_118107773

I get it, but like I said for me and many others a heat pump is too expensive. And this is really for the future as I expect to get a few more years from the gas boiler.

antoinolachtnai

Then best (cheapest to buy, run, greenest) option is probably another gas boiler.

Sleeper12

https://www.boards.ie/discussion/comment/118108517#Comment_118108517

I 100% agree

A combi electric boiler capable of heating a home quickly would require 3 phase I think. An electric shower is 9kw and can only heat around 3 litres of warm water per minute on a cold day. Rads require hotter water than an electric shower. I can't see a combi boiler heating a house on single phase electricity.

Wearb

House needs about 20/30 kW of heating to have it equivalent to oil heating. Depending on house size, that would be what's roughly required with an oil boiler or any heating source to match the same heat up time.

mad m

Plus isn’t it all down to the HLi for a house to warrant install of a heat pump

ercork

https://www.boards.ie/discussion/comment/118108517#Comment_118108517

Completely agree.

bullpost

https://www.boards.ie/discussion/comment/118108517#Comment_118108517

And I suspect thats what a lot of those households the government plan to persuade to move to heat pumps will also conclude.

Having looked at running costs for an electric boiler compared to a gas boiler, I'm beginning to think its not really viable as the regular bills for heating a home would increase so much. Government will have to provide very hefty grants to facilitate any mass move among existing households to heat pumps realistically.

Sleeper12

A lady pulled me up on a comment I made on another thread about having heating on for 4 months of the year. She said this is Ireland & we need it on for 6 months or more. Here's the thing, Ireland is a very mild country. It's not that it's cold that so many homes need heating on for more than half of the year. These homes need heat for most of the year because of bad insulation. Anyone thinking about heat pumps need to bring their insulation up to a very high standard. Air to water in particular will struggle to hold temperature on cold days. Most homes would need to double the size of their rads for air to water.

OP have a look at split mini heat pumps. This might be a solution for you. Sized correctly they can heat your whole home.

From an environmental point of view heat pumps have a downside too. They are also air conditioners so people will run them during the summer

John.G

https://www.boards.ie/discussion/comment/118110119#Comment_118110119

I think a HLI of 2 or < is the "economic" level for installing a HP.

I have put a few numbers together based on this and my own house area, I consume ~ 15000 kwh of oil/annum. I have assumed a COP of 2.8 but you can input any values you like in any of the yellow bcells.

HLI rev1.xlsx