Is your energy supplier going bust?

Discussions about serious topics, for serious people
IvanV
Snowbonk
Posts: 504
Joined: Mon May 17, 2021 11:12 am

Re: Is your energy supplier going bust?

Post by IvanV » Mon Oct 11, 2021 3:58 pm

purplehaze wrote:
Sat Oct 09, 2021 11:12 am
I've had two speculative letters from companies wanting to install heat pumps - 'FREE OF CHARGE'
This can be true, if you have the right house. But be careful of what you wish for.

There is a government grant available to support the installation of heat pumps. Depending upon the size of the job - usually has to be about an average 3-bed house - and a sufficiently straightforward installation, then it can work out that the grant is sufficient to cover the cost of the heat pump and its installation.

It will be an air source heat pump, so a backwards aircon unit. Ground source heat pumps are a lot more expensive and the grant does not cover the full cost of those.

But there are two important issues as to whether this "free heat pump" is worth it:

Will you be sufficiently warm if you have an air source heat pump?
What will it cost to run?

Air source heat pumps deliver lower grade heat than your gas boiler, so the water in your rads will not be as hot. Unless your house is very well insulated, or your rads are seriously oversized for the current job, you might not be warm enough during the coldest part of the year. Unless your house is already arranged to the very high standards of insulation of recently built new houses, it might be very expensive to upgrade the insulation sufficiently, and/or increase size of the rads, such that the air source heat pump does the job. New houses with a heat pump would typically choose underfloor heating, or fanned air heating such as more commonly found in commercial premises, rather than conventional rads, so that the lower grade heat can do its job without being obtrusive with big rads. Many people choose to have a supplementary source of heat for the coldest days of the winter if they have an air source heat pump. It is mainly installed at locations off the gas grid, where they cannot access the cheap price of piped gas. It is most popular in places like SW Wales and SW Scotland where they have mild winters and no piped gas.

The heat uprate of a good air source heatpump is a factor of 3 - ie it pumps 3 times as much heat as it uses. But in recent times electricity has generally been about 5 times the cost of gas per kWh. Modern gas boilers run 90% efficient, so in money the ratio is about 4.5:3 rather than 5:3. But in general that means that running a heat pump costs 50% more in money to get the same amount of useful heat, on average.

Currently the prices of electricity and gas are all over the place and it remains to be seen where they will settle down. If a large increase in the price of gas becomes settled, then I would expect the elec:gas price ratio to fall from its current 5:1 to something a bit lower. But it needs to get below 3.3:1 for heat pumps to become cheaper to run than a gas boiler in the same house.

User avatar
mediocrity511
Snowbonk
Posts: 405
Joined: Mon Nov 11, 2019 2:16 pm

Re: Is your energy supplier going bust?

Post by mediocrity511 » Wed Oct 13, 2021 7:12 pm

Well that's my Energy supplier gone, Pure Planet. They were hedged into spring but it looks like BP pulled their funding. I must admit to being slightly naive and not even realising they were funded by BP when I signed up.

User avatar
science_fox
Fuzzable
Posts: 333
Joined: Mon Nov 11, 2019 1:34 pm
Location: Manchester

Re: Is your energy supplier going bust?

Post by science_fox » Fri Oct 15, 2021 2:23 pm

IvanV wrote:
Mon Oct 11, 2021 3:58 pm
purplehaze wrote:
Sat Oct 09, 2021 11:12 am
I've had two speculative letters from companies wanting to install heat pumps - 'FREE OF CHARGE'
This can be true, if you have the right house. But be careful of what you wish for.

There is a government grant available to support the installation of heat pumps. Depending upon the size of the job - usually has to be about an average 3-bed house - and a sufficiently straightforward installation, then it can work out that the grant is sufficient to cover the cost of the heat pump and its installation.

It will be an air source heat pump, so a backwards aircon unit. Ground source heat pumps are a lot more expensive and the grant does not cover the full cost of those.

But there are two important issues as to whether this "free heat pump" is worth it:

Will you be sufficiently warm if you have an air source heat pump?
What will it cost to run?

Air source heat pumps deliver lower grade heat than your gas boiler, so the water in your rads will not be as hot. Unless your house is very well insulated, or your rads are seriously oversized for the current job, you might not be warm enough during the coldest part of the year. Unless your house is already arranged to the very high standards of insulation of recently built new houses, it might be very expensive to upgrade the insulation sufficiently, and/or increase size of the rads, such that the air source heat pump does the job. New houses with a heat pump would typically choose underfloor heating, or fanned air heating such as more commonly found in commercial premises, rather than conventional rads, so that the lower grade heat can do its job without being obtrusive with big rads. Many people choose to have a supplementary source of heat for the coldest days of the winter if they have an air source heat pump. It is mainly installed at locations off the gas grid, where they cannot access the cheap price of piped gas. It is most popular in places like SW Wales and SW Scotland where they have mild winters and no piped gas.

The heat uprate of a good air source heatpump is a factor of 3 - ie it pumps 3 times as much heat as it uses. But in recent times electricity has generally been about 5 times the cost of gas per kWh. Modern gas boilers run 90% efficient, so in money the ratio is about 4.5:3 rather than 5:3. But in general that means that running a heat pump costs 50% more in money to get the same amount of useful heat, on average.

Currently the prices of electricity and gas are all over the place and it remains to be seen where they will settle down. If a large increase in the price of gas becomes settled, then I would expect the elec:gas price ratio to fall from its current 5:1 to something a bit lower. But it needs to get below 3.3:1 for heat pumps to become cheaper to run than a gas boiler in the same house.
That's interesting and useful to know thanks.
Of course it neglects to include the externalities cost of preventing climate change and how much extra you'd have to pay for the increased risk of flooding/drought/food etc etc. I'll admit it could be tricky to calculate that as a per/month figure, what would you pay now to help avoid having to pay more later, which in turn pre-supposes that the generic 'you' has enough surplus income to make that choice.
I'm not afraid of catching Covid, I'm afraid of catching idiot.

User avatar
dyqik
Light of Blast
Posts: 4319
Joined: Wed Sep 25, 2019 4:19 pm
Location: Masshole
Contact:

Re: Is your energy supplier going bust?

Post by dyqik » Fri Oct 15, 2021 3:48 pm

IvanV wrote:
Mon Oct 11, 2021 3:58 pm

Air source heat pumps deliver lower grade heat than your gas boiler, so the water in your rads will not be as hot. Unless your house is very well insulated, or your rads are seriously oversized for the current job, you might not be warm enough during the coldest part of the year. Unless your house is already arranged to the very high standards of insulation of recently built new houses, it might be very expensive to upgrade the insulation sufficiently, and/or increase size of the rads, such that the air source heat pump does the job. New houses with a heat pump would typically choose underfloor heating, or fanned air heating such as more commonly found in commercial premises, rather than conventional rads, so that the lower grade heat can do its job without being obtrusive with big rads. Many people choose to have a supplementary source of heat for the coldest days of the winter if they have an air source heat pump. It is mainly installed at locations off the gas grid, where they cannot access the cheap price of piped gas. It is most popular in places like SW Wales and SW Scotland where they have mild winters and no piped gas.

The heat uprate of a good air source heatpump is a factor of 3 - ie it pumps 3 times as much heat as it uses. But in recent times electricity has generally been about 5 times the cost of gas per kWh. Modern gas boilers run 90% efficient, so in money the ratio is about 4.5:3 rather than 5:3. But in general that means that running a heat pump costs 50% more in money to get the same amount of useful heat, on average.
The actual achieved efficiency can be a bit more complex than this. My experience is with air source heat pumps and gas furnaces for forced hot air heating, but it should mostly be transferrable to forced hot water heating.

A typical gas boiler and radiator system is oversized for the heating system for 90-95% of the usage (it's sized for the coldest nights), and cycles on and off with the thermostat. It might have two levels of heat available, but it won't achieve the same efficiency in both levels. An air-source heat pump will cycle less, and newer ones are variable power, and throttle back rather than cycling, so that they run at a continuous lower output, which is generally more efficient than the maximum output power. By throttling back rather than cycling, there's less wastage of heat (heat loss through walls behind radiators or from pipes to places you don't need it increases with the temperature difference).

I think cooler radiators running continuously should give a better, more comfortable sensible heat, as it doesn't overheat the water or air, and doesn't fluctuate. With forced hot air, we also see benefits from the forced air being less dry (overly dry air is a bigger issue here than dampness in winter - we have to run humidifiers to prevent nose bleeds etc.), but I'm not sure what effects lower temperature radiators have on the more common issue of dampness in the UK.

IvanV
Snowbonk
Posts: 504
Joined: Mon May 17, 2021 11:12 am

Re: Is your energy supplier going bust?

Post by IvanV » Fri Oct 15, 2021 5:32 pm

science_fox wrote:
Fri Oct 15, 2021 2:23 pm
Of course it neglects to include the externalities cost of preventing climate change and how much extra you'd have to pay for the increased risk of flooding/drought/food etc etc. I'll admit it could be tricky to calculate that as a per/month figure, what would you pay now to help avoid having to pay more later, which in turn pre-supposes that the generic 'you' has enough surplus income to make that choice.
It is very noble of you to think about avoiding externalities. Especially in the case of climate change, where those externalities are particularly hard to value, and you are so unlikely to get any quid pro quo back from it within your lifetime.

Most of us are conditioned to avoid certain externalities. If it's a kind of cooperation, that we can gain some internal happiness from, even though we don't know the people we are cooperating with, then it can happen. It's most likely when the externality is nevertheless shared and experienced within a sufficiently narrow community. So, for example, most of us don't drop litter because we don't like being in places that are covered in litter. So there is a fairly immediate quid pro quo - we don't drop litter in places we go, and the cooperation allows us to avoid suffering too much dropped litter in the places we go. But that is because the quid pro quo operates in a narrow community - the people who go to those places - and the costs on us all are fairly similar. And there are some people who don't care less and drop litter regardless. And if there are too many of them then the cooperative equilibrium is disturbed and those places become heavily littered. When there was a strike by litter collectors at Victoria Station in London, 10 or 20 years ago, soon the concourse was drowning in littler. Litter was being dropped at a rate sufficient to completely cover the concourse to a depth of about 5cm per day. Apparently too many people pass through such a place to get a sense of community with the other passers-by.

For climate change, the community we require cooperation over is the whole world. And for most inhabitants of this planet, the cost to them of avoiding CO2 output is much higher than for us - maybe they will miss the opportunity of a more comfortable lifestlye from their present pretty dire existence, perhaps.

I have argued that it is very important for us wealthy nations to cut hard to have a demonstration effect, to show we care. Because only then will we persuade the large producers to curtail their output, so that they might avoid the large costs to themselves, as well as to all of us. For most of us, the potential benefit is beyond our lifetime. CO2 has a long residence time in the atmosphere.

Whilst a bit of feel-good goes a long way, for most of us our heating system is sufficiently high in cost and important for our comfort that these will be a large element of our decisions over them. I tried very hard to justify putting in a lower carbon heating system when I had to change my boiler 3 years ago. But the cost of being green was just too large - even though unlike most owners of solid-walled houses I have already drylined them on the inside with 50mm of insulation. That insulation decision (now 20 years old) was in fact the best value green thing I could do, saving me money as well as reducing CO2 output, and many people won't even do that.

User avatar
nekomatic
Catbabel
Posts: 660
Joined: Mon Nov 11, 2019 3:04 pm

Re: Is your energy supplier going bust?

Post by nekomatic » Fri Oct 15, 2021 6:41 pm

Gas boilers can do variable output for heating, and it’s a mystery to me why it’s not either required by regulation (as I believe it is in some European countries) or suggested by installers. I think the extra cost to put it on our system was less than two hundred quid, but we only got it because I was geeky enough to find out about it and get the installer to do it.
Dervict stanord

Post Reply