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  • Writer's pictureThe Climate Coach

Insulate Britain - they’ve got a point to be fair!

When it comes to home insulation, the UK - despite its generally cold and rainy climate, has quite poorly insulated homes which means we use a lot of energy to heat them. Insulating them seems like a very sensible idea to help reduce our overall energy need - and thus emissions for heating.

Just insulate homes more - easy right?

In some cases yes! Where a home should have insulation as per it's design but doesn't - then yes absolutely adding insulation will (sometimes significantly) reduce the energy needed to heat the home. This could be missing loft insulation or wall insulation. If it's just been missed by the builders or has been removed for some reason (e.g. through renovation), then adding it back shouldn't have any negative impact elsewhere.

However, adding additional insulation beyond the original home design can be more complex and it mainly comes down to ventilation and damp prevention. All homes need ventilation to help prevent damp and mould build up inside. This is done in a number of different ways depending on the house but will usually be one or more of the following:

  • Extractor fans in bathrooms

  • Trickle vents around windows and door

  • Mechanical ventilation (a fan which circulates air around the house and removes the moisture in the process)

  • Natural ventilation from opening doors and windows.

On an older property though, there is probably also additional ventilation from poorly fitted or aged/damaged doors and windows, which will let air in around the edges.

Why does adding insulation impact ventilation though?

Well it doesn't always but it can do if not done correctly. Warm moisture in homes - from us breathing and when we cook, have showers or baths - requires ventilation to prevent it sticking around and becoming damp and ultimately mould. When there isn't sufficient ventilation, the moisture will look for cold surfaces to stick to - which is where it will become condensation. Left unchecked, this will very quickly become mould which can be harmful for human health. When large surface areas are cooler at the same temperature - the moisture spreads out and often won't present itself as condensation as a result. So when insulation is added to a poorly ventilated house, that large surface area can become smaller - effectively causing condensation on "cold spots" which can subsequently turn into mold. These cold spots are sometimes unavoidable - e.g. around pipe entries or around electrical equipment which cannot be insulated for safety reasons. Or it could just be around windows and doors where it can sometimes be colder - as in the thermal image above of a poorly fitted door.

How do you have really good insulation AND avoid damp/condensation then?

In a Passivhaus (which is basically a really well insulated home that requires hardly any heating or cooling), the home is very very heavily insulated all round and has very high airtightness standards - meaning there are no window trickle vents for example. All windows and doors have to be built to a very high standard and fitted well to avoid thermal bridging or any air ingress. As a result, ventilation usually needs to be done with mechanical ventilation - which extracts moisture from the air as it circulates. This typically involves running ducting to every room and having some space for the system to live. The energy requirements of these types of houses are usually extremely low with the main energy requirement usually being to run the mechanical ventilation.

So back to a "normal" home, even if you insulated your home to a very high standard, as per a Passivhaus - which is very difficult and requires almost everything to be upgraded, it's unlikely you would want to retro-fit the mechanical ventilation system ducting and/or even have space for it to live. Hence it's probably not feasible to try and do this to every home. Of course, this isn't even considering the initial costs involved which would be significant as most homes weren't designed for this in the first place. Insulation obviously generally requires thicker walls for the insulation to live so sometimes to do that you would either have to expand outside or take up valuable living space inside.

This sounds pretty what is the answer then?

Well every home is different and thus is in a differing state in terms of energy demands to heat it. So one approach just won't work. We urgently need to reduce the energy required to heat our homes though so it will need a few things to happen:

  1. Properly insulate all UK homes - this will involve a properly managed retrofit programme tackling the worst homes first.

  2. Improve airtightness in all UK homes - similar to the above or better still, as part of the same programme tackling the worst homes first.

  3. Drastically improve new build standards for insulation/airtightness

Unfortunately, new build homes in the UK are still being built in way which requires them to use a huge amount of energy to heat them - and at the moment the only solution to that is a big gas boiler. This is I assume in an attempt, to keep house prices down but in effect, it's just pushing the cost further down the line to the heating bills for the homeowner/tennant. An extra investment when the house is built should easily pay for itself in the lifetime of the house. There is a reason many homeowners invest in solar panels or proper insulation - because it generally pays for itself over time plus adds value to their house if they sell or rent out.

Ok - but what can I do though?

Good point - clearly you can't just go out and start insulating other peoples homes. As a start, I would recommend the following:

  1. Read our posts about how to improve airtightness in your home and try to improve yours (and your bills). This could really help reduce your gas usage. You don't have to own your home to do this - but if you rent, demand issues are resolved by your landlord.

  2. Check insulation in your home - or any home you are looking to buy or rent. If in doubt - ask for advice. Again, demand issues are resolved by your landlord if you rent. If buying a house, request that issues are resolved as part of your purchase. Prioritise efficiency in your purchase/rental decisions. (Don't just rely on the EPC rating - but more on that in another post)

  3. Consider investing in improving your home to reduce energy consumption because for heating, this is usually gas. This doesn't have to cost a load of money - and with prices as they are now at time of writing (February 2023), this could well be the best investment in terms of return that you can make now anyway. It could be airtightness strips on doors and windows or some additional loft insulation. Our post on airtightness can really help you find some simple and common areas to be improved. We have some posts about solar panels if you are considering these and also a detailed post on reducing electricity usage you might be interested in too - although electric use isn't directly using gas, much of the UK electricity supply still comes from fossil fuels.

If you have any thoughts, feedback or ideas you wish to contribute on this or any other topic covered by The Climate Coach - please get in touch, we'd love to hear from you.

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