People Saying Heat Pumps are Rubbish - Are They?

michaels

grumpypensioner said:

Best honest account I have yet read, I agree totally. Technology has much to offer, each current component version helps contribute but does not yet give a single complete solution. We need to blend "hybrid" approaches to achieve overall success of economy.
So don't just invest in one single large item of equipment, spread the load. I am personally impressed with my free standing air conditioner which rapidly heats/cools/dehumidifies my downstairs all for less than £500 capital outlay thus significantly reducing the load off my central heating system bills.
Would be good to hear other experiences?

What unit is that and what venting/exhaust do you have?  is it noisy?

benson1980

grumpypensioner said:

Best honest account I have yet read, I agree totally. Technology has much to offer, each current component version helps contribute but does not yet give a single complete solution. We need to blend "hybrid" approaches to achieve overall success of economy.
So don't just invest in one single large item of equipment, spread the load. I am personally impressed with my free standing air conditioner which rapidly heats/cools/dehumidifies my downstairs all for less than £500 capital outlay thus significantly reducing the load off my central heating system bills.
Would be good to hear other experiences?

160sq m 1970s house. Suspended floor no insulation. Cavity wall insulation albeit chalet bungalow style and quite poorly insulated dormers upstairs. 100mm loft insulation.

previous system- heat only gas boiler. [noisy] ch pump in airing cupboard. Around 20000 kW gas per year. Set back to 16 at night, and when out. Set backs not ideal as house uncomfortably cold at these times/when returning home.

3.7kW solar array already installed (previous owner)

12kW ashp installed nov last year. HW cylinder set at 48oC. Battery installed not long after. Total outlay13k (ashp around 5500). House at 20.5 degrees continuously. 

Without battery I worked out our winter bills would have been around £30 more per month than gas. Savings in the spring, summer and autumn months. With battery we saved around £120-150ish per month in Jan- March taking advantage of tariff dips and storing electricity. (Octopus cosy). Now sun is out and it’s a bit warmer our energy costs are really low.

Vastly more comfortable house- no comparison, would never want to go back to non weather compensation and set back temps. With battery I would estimate we will save around £800 a year. Hot water no issues. Flow temp for cylinder reheat is separate to CH. 

no regrets (apart from choice of installer- not great). Without solar and battery I think we’d likely be similar cost to gas but this is at constant comfortable indoor temp + no set backs as above. When referring to electricity being 4 times more expensive no boiler is 100% efficient so Ashps do not necessarily need to run at a scop of 4 to break even. Some might also argue only one way the price disparity can go in future and gas more expensive/electricity cheaper.

Spoonie_Turtle

grumpypensioner said:

Jolly good, obviously done their homework for their situation. Why not get them to leave descriptions of their circumstances to help others. Three down and the rest of the world to go.

There are TONS of threads, on this board, on the green energy board, on other fora. 

I have commented about our situation several times across different threads.  I've also expressed concerns for people who like us have a heat pump put in by the landlord - often social housing - with no guidance, no helpful documents (I literally can't even find a comprehensive manual for our unit online despite searching several times over the years) and without the capacity to learn from others online.  BUT that is not the fault of the technology, that's the fault of the people involved leaving us with the instructions of 'the installers have set it up, you can change the room temp but otherwise don't touch anything; if you have any problems phone us'.  Although to be fair the default setting they leave it does keep the house and water warm!

Exiled_Tyke

matelodave said:

The general consensus is that a properly spec'd system, properly installed, commissioned and used correctly is efficient, will keep you warm and if you are lucky might save you money. But saving money depends on how you heated your home previously, the cost of leccy compared with what you used before and how much it costs to install it all in the first place.

When I got my system installed it replaced manky old storage heaters (we dont have mains gas), oil was expensive as was LPG and with a lot of scratching around we managed to get good electricity prices (although five of the suppliers went bust until it all fell apart).

Nowadays the per kwh cost of oil is around the same as mains gas but leccy is nearly four times the price so you need to achieve a SCOP of around four just to break even.

The problem is still the up front cost, so if you can get the system running with a SCOP of better than four then you need to do the sums to work out when you'll be in profit. I know you can install batteries and solar panels, but again you need to do a proper analysis to work out how long its  going take you to pay back, especially if you have to borrow money to pay for it all or lose interest or dividends on your capital.

I reckon I just about broke even a few years ago as we've now had our system for just under 15 years but I'm not sure that the SCOP of my system balances the cost of electricity versus oil or gas at the moment.

I dont feel inclined to splash out on solar or batteries at the moment as at 78 I doubt I'll live long enough to break even.

Some interesting perspective here and I reckon you've got it pretty much spot on.  My main driver in getting an ASHP was not to save money but it looks like I will.   I have a decent EV tariff so can heat water overnight and 'kick start' the space heating on a morning on the cheap tariff.  In the shoulder months (like now) I'm also getting some 'free' heat from my solar panels (it's not worth me using a export tariff as already I use most of my production).       Hopefully electricity prices will also become more sensible in time. The current price compared to gas is ridiculous and is doing nothing to help people move towards renewable energies. 

NedS

Exiled_Tyke said:

matelodave said:

The general consensus is that a properly spec'd system, properly installed, commissioned and used correctly is efficient, will keep you warm and if you are lucky might save you money. But saving money depends on how you heated your home previously, the cost of leccy compared with what you used before and how much it costs to install it all in the first place.

When I got my system installed it replaced manky old storage heaters (we dont have mains gas), oil was expensive as was LPG and with a lot of scratching around we managed to get good electricity prices (although five of the suppliers went bust until it all fell apart).

Nowadays the per kwh cost of oil is around the same as mains gas but leccy is nearly four times the price so you need to achieve a SCOP of around four just to break even.

The problem is still the up front cost, so if you can get the system running with a SCOP of better than four then you need to do the sums to work out when you'll be in profit. I know you can install batteries and solar panels, but again you need to do a proper analysis to work out how long its  going take you to pay back, especially if you have to borrow money to pay for it all or lose interest or dividends on your capital.

I reckon I just about broke even a few years ago as we've now had our system for just under 15 years but I'm not sure that the SCOP of my system balances the cost of electricity versus oil or gas at the moment.

I dont feel inclined to splash out on solar or batteries at the moment as at 78 I doubt I'll live long enough to break even.

Some interesting perspective here and I reckon you've got it pretty much spot on.  My main driver in getting an ASHP was not to save money but it looks like I will.   I have a decent EV tariff so can heat water overnight and 'kick start' the space heating on a morning on the cheap tariff.  In the shoulder months (like now) I'm also getting some 'free' heat from my solar panels (it's not worth me using a export tariff as already I use most of my production).       Hopefully electricity prices will also become more sensible in time. The current price compared to gas is ridiculous and is doing nothing to help people move towards renewable energies. 

Agree with everything above.

On the subject of the difference between electricity and gas prices, I cannot understand why the cost of the green levies which help pay for FiTs, ROCs etc are not shifted from the electricity bills onto the gas bills.

Why are we taxing the 'clean' energy source which we are trying to encouraging people to move towards instead of the 'dirty polluting' energy source we are trying to encourage people to move away from?

If the government moved some of the levies onto the gas bill to maintain a price difference of no more than 3 times, then those with a COP of 3 (easily achievable) will pay no more and those with COPs of 4-5 can make significant savings which will help drive the uptake.

We need to make gas more expensive and electricity cheaper to drive change, and the government have the tools at their disposal to do that through taxation.

hairydog

Having just read through this thread (all 10 pages) a few things come to mind, so although these are responses to comments, there are no references.
1. Having a few thousand pounds of spare equity doesn't make buying (anything) a good idea. Always have at least three months income in the bank.
2. Electricity costs four times as much as mains gas, so unless the COP averages well over 4, running costs will be higher. COP's always worst in cold weather when you use most heating.
3.Noisy heat pump external units are usually caused by the fans not being level. The unit may have been installed level, but if the slab wasn't good enough, one side may drop a bit. Also they need to be surrounded by sound absorbent surfaces that let the air flow through.
4. Sealing your house up to prevent draughts is bad for your health, bad for the building, and in the long term will cause structural damp that will increase heating bills. If you want to stop cold draughts by sealing ventilation, you also need mechanical ventilation with heat recovery.
5. Insulating always makes sense. The relatively high running cost of ASHP just makes more insulation more cost effective. They work without it - at a price.
6. ASHP systems don't seem to last very long. A decent gas boiler lasts 15 to 25 years, with a service every 3-5 years. I know of a few people whose ASHP unit has had to be replaced before it was ten years old (one of them twice in ten years). This has a huge embedded carbon cost.
So in summary, ASHP do work, but they probably won't save you money and they are no greener than mains gas.
My expectation is that before gas boilers are phased out, we shall see the gas mains used to distribute green hydrogen, made from off-peak excess renewable electricity.

MeteredOut

NedS said:

Exiled_Tyke said:

matelodave said:

The general consensus is that a properly spec'd system, properly installed, commissioned and used correctly is efficient, will keep you warm and if you are lucky might save you money. But saving money depends on how you heated your home previously, the cost of leccy compared with what you used before and how much it costs to install it all in the first place.

When I got my system installed it replaced manky old storage heaters (we dont have mains gas), oil was expensive as was LPG and with a lot of scratching around we managed to get good electricity prices (although five of the suppliers went bust until it all fell apart).

Nowadays the per kwh cost of oil is around the same as mains gas but leccy is nearly four times the price so you need to achieve a SCOP of around four just to break even.

The problem is still the up front cost, so if you can get the system running with a SCOP of better than four then you need to do the sums to work out when you'll be in profit. I know you can install batteries and solar panels, but again you need to do a proper analysis to work out how long its  going take you to pay back, especially if you have to borrow money to pay for it all or lose interest or dividends on your capital.

I reckon I just about broke even a few years ago as we've now had our system for just under 15 years but I'm not sure that the SCOP of my system balances the cost of electricity versus oil or gas at the moment.

I dont feel inclined to splash out on solar or batteries at the moment as at 78 I doubt I'll live long enough to break even.

Some interesting perspective here and I reckon you've got it pretty much spot on.  My main driver in getting an ASHP was not to save money but it looks like I will.   I have a decent EV tariff so can heat water overnight and 'kick start' the space heating on a morning on the cheap tariff.  In the shoulder months (like now) I'm also getting some 'free' heat from my solar panels (it's not worth me using a export tariff as already I use most of my production).       Hopefully electricity prices will also become more sensible in time. The current price compared to gas is ridiculous and is doing nothing to help people move towards renewable energies. 

Agree with everything above.

On the subject of the difference between electricity and gas prices, I cannot understand why the cost of the green levies which help pay for FiTs, ROCs etc are not shifted from the electricity bills onto the gas bills.

Why are we taxing the 'clean' energy source which we are trying to encouraging people to move towards instead of the 'dirty polluting' energy source we are trying to encourage people to move away from?

If the government moved some of the levies onto the gas bill to maintain a price difference of no more than 3 times, then those with a COP of 3 (easily achievable) will pay no more and those with COPs of 4-5 can make significant savings which will help drive the uptake.

We need to make gas more expensive and electricity cheaper to drive change, and the government have the tools at their disposal to do that through taxation.

A significant percentage of electricity is produced by burning gas.

Around 30% in the last year

https://grid.iamkate.com/

QrizB

MeteredOut said:

A significant percentage of electricity is produced by burning gas.
Around 30% in the last year
https://grid.iamkate.com/

While that is true, the carbon Intensity of the electricity grid is around 100-150g CO2 per kWh, while burning gas is a little over 200g per kWh.
Direct electric heating produces lower carbon emissions than a gas boiler. A COP 3 heat pump is around 1/4 to 1/6 of the emissions of a gas boiler.

FreeBear

hairydog said: My expectation is that before gas boilers are phased out, we shall see the gas mains used to distribute green hydrogen, made from off-peak excess renewable electricity.

There are major issues with hydrogen. For a starter, the current distribution system is not capable of shipping hydrogen safely (look up hydrogen embrittlement). Nor do we have the generational capacity to produce & store sufficient "green" hydrogen to supply all the homes in the UK. Sure, both generation/storage and shipping can be solved by investment, but it would be at a huge cost. On top of that, all the installed gas boilers would need modifications before they could burn hydrogen.

The government has postponed the Redcar hydrogen scheme until 2026 at the earliest - In all probability, it will be quietly dropped. In the meantime, another take on the hydrogen debate - https://www.heatgeek.com/the-great-hydrogen-boiler-conspiracy/

benson1980

hairydog said:

2. Electricity costs four times as much as mains gas, so unless the COP averages well over 4, running costs will be higher. COP's always worst in cold weather when you use most heating.

No boiler is 100% efficient. Thus an ASHP does not need to be more than 400% efficient to just break even. The SCOP is the important figure when projecting costs/savings over the course of a year and anything around 3.8 will likely be similar cost to gas or potentially provide a small saving.