Is it worth getting a new gas installation in 2023?

Qyburn

If you're worried about the ethics of gas heating at this time, remember that a lot of our electricity comes from burning gas. Gas is the only source that can readily be turned up and down. So arguably a new electrical demand, like someone switching from gas to ASHP, is fuelled entirely from gas.

matt_drummer

Qyburn said:

If you're worried about the ethics of gas heating at this time, remember that a lot of our electricity comes from burning gas. Gas is the only source that can readily be turned up and down. So arguably a new electrical demand, like someone switching from gas to ASHP, is fuelled entirely from gas.

Yes, but a heat pump powered by electricity generated from burning gas will be around 300% efficient.

That means a third of the amount of gas is consumed in running a heat pump compared to any other form of heating powered by electricity and even less compared to a gas boiler which is less than 100% efficient. And all that is assuming that all of the electricity consumed by the heat pump is generated using gas.

Andreg

Why is a heat pump not an option?   If it's unfeasible to switch to heat pump in future that makes putting in a gas powered wet system now a risky option.

matt_drummer

Andreg said:

Why is a heat pump not an option?   If it's unfeasible to switch to heat pump in future that makes putting in a gas powered wet system now a risky option.

Location, planning, things like that I would imagine.

ArbitraryRandom

matt_drummer said:

Qyburn said:

If you're worried about the ethics of gas heating at this time, remember that a lot of our electricity comes from burning gas. Gas is the only source that can readily be turned up and down. So arguably a new electrical demand, like someone switching from gas to ASHP, is fuelled entirely from gas.

Yes, but a heat pump powered by electricity generated from burning gas will be around 300% efficient.

That means a third of the amount of gas is consumed in running a heat pump compared to any other form of heating powered by electricity and even less compared to a gas boiler which is less than 100% efficient. And all that is assuming that all of the electricity consumed by the heat pump is generated using gas.

I don't think it actually works that way. 

You need to burn more gas to produce electricity in the home than you do if you just burn the gas in the home (it's a lossy process that's only around 40% efficient). 

Ignoring electricity from renewables, I think in terms of 'resource consumption' it's heat pump, boiler (assuming high 80% efficiency condensing boiler), then electricity produced from gas. 

QrizB

ArbitraryRandom said:

Ignoring electricity from renewables, I think in terms of 'resource consumption' it's heat pump, boiler (assuming high 80% efficiency condensing boiler), then electricity produced from gas. 

Carbon intensity (the amount of CO2 emitted for each kWh of energy) is a fascinating topic.

According to Wikipedia, a CCGT electricity generating station might emit 410-640g of CO2 for each kWh generated. However, gas supplies a minority (less than a third) of the UK's electricity.

The average carbon intensity of the UK electrical grid over the past 12 months is about 151g. Data from Drax. A heat pump with a COP of 3 would have an effective carbon footprint of ~50g/kWh.

The carbon intensity of a kWh of natural gas (before allowing for boiler inefficiency) is 202g/kWh (from Forest Research, UK gov site).Burned in an 80% efficient boiler, that's 252g of CO2 per kWh of useful heat.

So, based on these figures, it seems that a gas boiler is considerably more polluting (in terms of carbon footprint) than direct electric heating is.

Considering a typical property with a 10,000kWh/yr heat demand:

• Gas in an 80% efficient boiler: 2.5 tonnes of CO2/yr
• Direct electric heat: 1.5 tonnes of CO2/yr
• Heat pump with COP of 3: 0.5 tonnes of CO2/yr.

ArbitraryRandom

QrizB said:

ArbitraryRandom said:

Ignoring electricity from renewables, I think in terms of 'resource consumption' it's heat pump, boiler (assuming high 80% efficiency condensing boiler), then electricity produced from gas. 

Carbon intensity (the amount of CO2 emitted for each kWh of energy) is a fascinating topic.

According to Wikipedia, a CCGT electricity generating station might emit 410-640g of CO2 for each kWh generated. However, gas supplies a minority (less than a third) of the UK's electricity.

The average carbon intensity of the UK electrical grid over the past 12 months is about 151g. Data from Drax. A heat pump with a COP of 3 would have an effective carbon footprint of ~50g/kWh.

The carbon intensity of a kWh of natural gas (before allowing for boiler inefficiency) is 202g/kWh (from Forest Research, UK gov site).Burned in an 80% efficient boiler, that's 252g of CO2 per kWh of useful heat.

So, based on these figures, it seems that a gas boiler is considerably more polluting (in terms of carbon footprint) than direct electric heating is.

Considering a typical property with a 10,000kWh/yr heat demand:

• Gas in an 80% efficient boiler: 2.5 tonnes of CO2/yr
• Direct electric heat: 1.5 tonnes of CO2/yr
• Heat pump with COP of 3: 0.5 tonnes of CO2/yr.

Yes, sorry I wasn't clear - I was comparing directly using gas vs using electricity from gas (as we move to a greater portion of electricity generated from renewables, of course it's going to be less polluting) 

i.e it's not the efficiency of the boiler that's the issue as generating electricity from gas is even less efficient. 

wrf12345

There is a type of air to air heat pump that is mounted internally, all in one monoblock system, and requires two five inch holes drilled through the wall to the outside so externally there are just a couple of vents. They are £600-1000 on ebay depending on size and retailer greed levels and do not require expensive install as the only connection required is an electrical socket, they are prepressurized and connected internally). Efficiency is down, probably COP under 3 in winter, but still cheaper than most alternatives. Potentially DIY, as it requires the two big holes and mounting holes. One of these in the lounge might be enough if insulation levels are good.

Gerry1

wrf12345 said:

There is a type of air to air heat pump that is mounted internally, all in one monoblock system, and requires two five inch holes drilled through the wall to the outside so externally there are just a couple of vents. They are £600-1000 on ebay depending on size and retailer greed levels and do not require expensive install as the only connection required is an electrical socket, they are prepressurized and connected internally). Efficiency is down, probably COP under 3 in winter, but still cheaper than most alternatives. Potentially DIY, as it requires the two big holes and mounting holes. One of these in the lounge might be enough if insulation levels are good.

Presumably an advantage is that it can also provide cooling in summer, but with the disadvantages that no grant is available, it takes up room space, and noise may be intrusive because it's emitted inside the house?

ArbitraryRandom

And, as I understand it, would require some time/cost for planning permission (I was advised anything with cooling functionality)?