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How can we tackle decarbonisation of heating in existing homes?
Question
Today’s best in class building and heating technologies provide many answers to the question – how will we tackle decarbonisation of heating in existing homes? Read our blog and comment below to let us know how we can embrace ‘best practice’, become an expert at it, and tell everyone that ‘good enough’ isn’t good enough anymore.
20 Replies
Simon Barker
923 Posts
It's all very well using better boilers with better control systems.  But it doesn't get round the problem that British housing stock is old and poorly insulated  Government schemes to address that have been shambolic, and haven't achieved much.

Even on new builds, enforcement of building regulations is pretty poor.  Housebuilders will build one house on an estate to meet regulations, then claim all the others are just the same, without any testing being carried out.
mapj1
3753 Posts
The easier solution is not to heat the houses, but to lag the people, in a jump back to the methods of a previous era, we could wear thicker pyjamas at night and more generally wear jumpers indoors, it is a lot cheaper and less wasteful of resources. There is no need to heat the whole house to a temp where you can walk around in your underwear and not feel cold.
This light-hearted sketch purports to show the effect of global warming, but what it  really demonstrates is increasing personal fuel consumption in recent times.

Mike

Mike.
Zoomup
3131 Posts
Plant a tree.

Z.
Hi Simon
The article does mention the importance of insulation and double glazing, the 'fabric first' approach is well established and should always be addressed irrespective of the heating system. Indeed to obtain Domestic RHI payments the assessors will insist on improvements to an acceptable standard before approving the grants.
Rob 
Love it Mike

Rob
Zoomup:
Plant a tree.

Z.

Indeed, need to do that too. But trees take a few decades to become effective carbon sinks. We can stop producing the pollution today by simple changes to our homes and behaviours.

Rob

mapj1
3753 Posts
A second more serious point, and it aligns with Simon's more or less, is that we may well be better off persuading govt to invest in boring chemical research to say find ways to make aerogel-like insulation in bulk, and better insulating fabrics for curtains rather than spending millions on  fancy computerised what-nots that allow you to be cloud connected so you can run a bath from the other side of the  planet, and the software will be out of support in 5 years, long before any modest saving has paid back..
"Negawatts"  of not needing the heating turned on at all are worth far more than millisecond precision remote controls.
The use of heat reflecting paints and surface treatments  is a similar totally non-sexy but necessary thing to be done.

The article in the original link sort of sets off on the wrong foot in my  opinion - buildings will be demolished and rebuilt over a period of centuries, maybe rather more in the UK and less in places like the US, and insulation upgrades need to  be cost effective over a decade or two, (see the other post on overprice passivhaus ) the only instant win that most working folk, especially those in rented accommodation can do within  a time-scale of perhaps a year  is a change of clothes.

Mike.

(and beware of forcing landlords to upgrade - the money to do that has to come from the tenants, the poorer of whom will then have to move to colder cheaper accommodation if the rent goes  up suddenly )
Zoomup
3131 Posts
Robert Whitney:
Zoomup:
Plant a tree.

Z.

Indeed, need to do that too. But trees take a few decades to become effective carbon sinks. We can stop producing the pollution today by simple changes to our homes and behaviours.

Rob

Don't trees naturally produce CO2 at night and Oxygen during the day? Do you really think that CO2 is "pollution"?

Z.

Roger Bryant
335 Posts
As others on here have said the real problem is Britain's housing design and expectations. Individual houses with solid or possibly cavity walls are not a good start.  If you look at the continental building styles, especially in the colder lands, multiple occupancy homes are the norm. This immediately reduces the surface area to volume ratio. Our apartment has two external surfaces. The other 4 surface are 'insulated' by other apartments.

The structure is usually a mixture of brick and concrete (wood in some areas) with a thick external layer of insulation (20-30cm) and then a hard waterproof skin. This allow the heavy structure to act as a heat buffer (in summer and winter)

Heating is usually by a wood or oil fired boiler serving all the apartments or sometimes a link to  a district heating scheme. A bigger boiler is generally more efficient, once again a better surface area to volume ratio.

How could we acheive something like this in Britain? Could we move peoples mindsets away from my home is my castle? Could we change the various building regulations to encourage an efficient build?
Thanks for this, ill be wearing lots of layers now and save a huge amount on money and CO2 emissions!
Simon Barker
923 Posts
Roger Bryant:
As others on here have said the real problem is Britain's housing design and expectations. Individual houses with solid or possibly cavity walls are not a good start.  If you look at the continental building styles, especially in the colder lands, multiple occupancy homes are the norm. This immediately reduces the surface area to volume ratio. Our apartment has two external surfaces. The other 4 surface are 'insulated' by other apartments.

The structure is usually a mixture of brick and concrete (wood in some areas) with a thick external layer of insulation (20-30cm) and then a hard waterproof skin. This allow the heavy structure to act as a heat buffer (in summer and winter)

Heating is usually by a wood or oil fired boiler serving all the apartments or sometimes a link to  a district heating scheme. A bigger boiler is generally more efficient, once again a better surface area to volume ratio.

How could we acheive something like this in Britain? Could we move peoples mindsets away from my home is my castle? Could we change the various building regulations to encourage an efficient build?

People in Britain want houses.  There's a "pecking order" with detached houses being the most desirable, then semi-detached houses, terraced houses, and flats at the bottom.  The terrible leasehold system in England really doesn't help with that (I believe Scotland has a better system).

House builders are only interested in knocking out estates full of standard houses of "traditional" build - i.e. brick cavity walls.  It's what they know how to do, and they can build them quickly and cheaply.

There's a lot of suspicion of district heating systems.  We have a regulator that controls the price of electricity and natural gas, but nothing else.  If you're on a district heating system, you have to pay whatever bills they choose to charge, with no say in how it's run.

KevinP
16 Posts
To answer the exam question: Costs of heat pump solution needs to be comparable to current gas boiler costs, preferably without subsidy. so we need to get lower installation costs, lower service charges and higher efficiency..  Air heat pumps are noisy and ugly too (Lets design better) and do not heat to a high enough temperature with standard radiators, so new builds must be underfloor heated and ground based heat pump where possible. Use smart meters to heat water cylinder at low cost off peak times (early morning). On existing properties need to get the price of air based heat pumps down and the service charges. Why so high? £250 pa quoted...see more below

Yesterday I helped a friend look at two options for heating his house, one a condensing boiler solution, the other an air based heat pump solution, complete with government grant. The energy consumption in KWH is reduced, maybe by a factor of 3. But the cost of electricity on my current EDF tariff is 5.8. times. The summary is that for similar heating, in a well insulated house ('A' rated glazing, cavity wall, OTT loft insulation) The heat pump solution costs an extra £31 pa on utility bills, assuming go all electric thus saving standing charge on Gas Heat pumps have longer life but cost more to replace and maintenance costs are quoted at £250 pa for the heat pump (£55 for gas) The overall cost comparison, including cost of replacement, every12 years for gas and 20 years for heat pump, include servicing too means heat pump solution costs an extra £400 pa approx (This is significant). CO2 would be less of course. Most of us want to go green, but not at any price. I wonder if current installers are 'making hay' while the sun shines, charging OTT for installation and maintenance. 

 
Hi Rob,
Could you post a list of the disruptive elements required to match up your ASHP to your system as you mention in your excellent blog?
Thanks
Simon Barker
923 Posts
Improving the efficiency of heat pumps is going to be tricky.  They should be able to deliver a COP of up to 4, but only if the heating system inside the house is very well designed (underfloor heating or big radiators), and if the heat source isn't allowed to get too cold.

Air source heat pumps are always going to be at the mercy of the weather.  That's not too bad in the South of England, but in the North of Scotland, temperatures below freezing aren't exactly unusual.

A well-specified ground source heat pump should do better.  But in small urban gardens, that means bringing in a drilling rig and drilling at least two deep boreholes to get a big enough heat source.
all the existing system had to be removed and repiped, space found for the new equipment including a low loss header, replacement cylinder and external heat pump unit.
the only thing that was original were the secondary pipework and rads.

I was without heat for 2 weeks and the whole project took 6 weeks, and there are still snags being addressed 
Zoomup:
Robert Whitney:
Zoomup:
Plant a tree.

Z.

Indeed, need to do that too. But trees take a few decades to become effective carbon sinks. We can stop producing the pollution today by simple changes to our homes and behaviours.

Rob

Don't trees naturally produce CO2 at night and Oxygen during the day? Do you really think that CO2 is "pollution"?

Z.

too much of anything can be considered pollution, especially things that are hazardous to human health (nox and particulates) and excess C02 that cannot be absorbed by the seas and plants. record high levels of  atmospheric co2 is increasing the greenhouse effect and raising global temperatures to levels that are having adverse effects on weather and ecosystems, fires, floods pestilance. but as a Professional Engineer you already knew that right?

Simon Barker:
Improving the efficiency of heat pumps is going to be tricky.  They should be able to deliver a COP of up to 4, but only if the heating system inside the house is very well designed (underfloor heating or big radiators), and if the heat source isn't allowed to get too cold.

Air source heat pumps are always going to be at the mercy of the weather.  That's not too bad in the South of England, but in the North of Scotland, temperatures below freezing aren't exactly unusual.

A well-specified ground source heat pump should do better.  But in small urban gardens, that means bringing in a drilling rig and drilling at least two deep boreholes to get a big enough heat source.

agreed but GSHP are another £££££ on top of an ASHP. community arrays are a great solution to this!

Helios
153 Posts
some pretty funny and whitty responses posted to this .
And as crazy as it sounds actually making a sort of lite heated full body garment really the least energy intensive system.
That aside the fixing up of poor thermal efficiency may not be the smartest use of money , the electrical heated (and cooled) house of modern construction is do able , and if we use (points to TRADA website) then even better is when you come to demolish your home (hopefully it lasting 150yrs or more) you have a biomass fuel supply for your electricty generation.
an amazing fact wood is it is the only material (as formed as a tree trunk) that gets stronger the drier it gets   
mapj1
3753 Posts
And as crazy as it sounds actually making a sort of lite heated full body garment really the least energy intensive system.
Not crazy at all, as any motor biker who is not fair weather only rider will confirm.
The artist may have been a bit carried away in this picture, but I can assure you that with the right clothing you can take the building away totally, and remain toasty warm in >> 50mph wind.... honestly officer, never more than 70mph...🙄
You do need the sleeves, gloves socks and trousers as well for full effect though. About 100 to 150 watts all up for the outdoor snowstorm. (examples)
Traffic police and similar are sometimes given ones that they can charge up in the car, and have a battery in the pocket for an hour or two of directing traffic or whatever.
Mike.

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