Some precisions about ways to warm your home efficiently

a follow up to the UK Permaculture Assoc. advice

The UK Assoc published a post on the social network that everyone likes to hate but continues using, to whit :

Simple Ways to Warm Your Home Efficiently:

🏡 Seal up draughts—use curtains, rugs, and door seals to keep the heat in.

🧥 Layer up—cozy blankets and warm clothing reduce the need to turn up the heat.

🔥 Insulate well—proper insulation can halve your heating needs.

🌞 Use natural warmth—let sunlight in during the day, to naturally warm your space.

🌱 Consider a full retrofit—for long-term savings and energy efficiency.

Let’s make smart, sustainable choices that keep us warm while reducing our climate impact!

The advice is a bit too simplistic so here’s some deeper stuff.

House insulation.

Before we think about producing, energy, heat, water or whatever we first analyse how needs can be reduced and waste eliminated. When we have done that we can then move on to exploring how to produce something.

From a Permaculture engineering perspective, insulation starts away from the house with the landscape. Using tree plantings, for example, to deflect cold winds or to channel cooling ones toward a building during hot weather or in tropical areas. These trees can also provide shade, their positioning, relative organisation, and distance from the house. When done well a good windbreak can reduce heating costs by 10 - 15%. They can reduce cooling costs by 15 - 20%. We would, of course, plant multi-functional trees and bushes.

Then we consider the building itself, insulating the outside or the inside? It depends on the building envelope, the local climate, cost, and material availability. The latter point is important as most of the products generally used to insulate the outside of a wall are not particularly environmentally friendly. Rigid EPS foam insulation panels, for example, are manufactured from polystyrene. This is a type of plastic, the manufacturers maintain that it can be recycled, but then they would say that. Cellulose and in particular cellulose structurally insulated panels are a better choice.

Insulating the inside of walls is generally cheaper, the simplest method is to replaster using a thermal insulation plaster. This is plaster with an insulating material in it. Aerogels are commonly used as the insulator but require synthetic molecules and an extensive manufacturing process. The company Aerodurit® produces a lime plaster with ‘microporous technology’, they maintain that their product is made from natural materials. ‘we manufacture almost all aerodurit® products using natural raw materials and without synthetic chemistry. They consist of high-quality raw materials in combination with special, purely natural, inorganic active ingredients. In production, we also focus on the highest quality and most sustainable production methods.’ That all sounds pretty good.

In most cases we would want a warm hat and socks on the house, so roof and underfloor (or on-floor) insulation is usually to be recommended. As Permaculture designers and engineers think generationally, we always, as far as possible, opt for materials that can be reused when their life as insulation ends.

You can be in a house that is at say 15°c and yet you don’t feel cold. You can be in another one that’s heated to 20°C and you find it a bit chilly. This is usually to do with the difference between the air temperature and that of the surfaces. Some materials, concrete, ceramic tiles, glass, etc feel cold to the touch. It feels as if they are drawing heat away from the body despite the warm air. If it’s the case then they need covering.

Relative humidity is another major player. Too low and our bodies evaporate more to the surrounding air making us feel cold. Too much humidity and the air feels heavy and uncomfortable and exacerbates the cold surface effect mentioned above. The ideal indoor relative humidity should be between 30 and 50 percent. Thermal insulating plasters can help with this. Airflow is a major consideration, a house should be able to ‘breathe’, get the ventilation right and the humidity levels should be easier to regulate.

A widely recommended way of dealing with excess humidity is the same as point 1 of the UK Assoc advice. Now tell that to the 1.9 million (7%) of households in the UK that use wood as a primary or secondary heating source. In this case, blocking up all the draughts and stopping all the air coming in from the outside is not the best idea. We can all remember learning that fires need oxygen and produce carbon monoxide and dioxide. The latter two aren’t a good substitute for the first. Again, everything depends on the context. Advice that doesn’t consider this can be dangerous.

The rest of the advice to too over-simplistic to be of any real use. Someone living in a cold damp house is unlikely to go around in their underwear. Insulation costs money, those people who are struggling to keep warm are usually those who have little money to spare. Using natural sunlight can be difficult for many households whose homes are predominantly in the shade. I have a friend whose house is in the shade all winter.

Real solutions are community-based and community-led. Nobody in my local area should be living in a cold and damp house, it shames us all. Instead of protesting with the government, we can simply get going and make sure that everyone’s house is comfortable. Insulation may not grow on trees but it can be grown in fields. A secondary, or indeed primary crop from the local community integrated farms can be insulation material. We can plant trees and bushes, it is our community after all. The local authority’s role should be to help integrate these initiatives, never to block them. If they do then get rid of the incumbents, sue them, or vote them out. We can no longer accept things like ‘heat or eat’, nor can we accept local ‘leaders’ who sit on their hands. It is shaming us all.