Baby It's Cold Outside
With Christmas right around the corner, our Santa’s wish list is taking shape on our second pilot at the Farmhouse . Whilst its fun to dream about the fancy kit, such as solar panels and cool battery storage solutions, the energy efficiency journey is a series of little steps. Some of the back-to-basics stuff like draught proofing is essential in a successful retrofit.
If there is to be a real movement towards Net Zero, it has been identified that natural gas needs to be eliminated from the domestic mix. The government has thrown its support behind the installation of ground and air source heat pumps. However, there needs to be a wider understanding that the heat pump is not a direct like- for- like replacement for our current forms of heating. They are more suitable for a longer, flat load profile, and will not send out that instant blast of heat when you feel a bit chilly. It is essential therefore, that the thermal performance of a building must be up to the job.
The barrier to this of course is capital cost. In a recent address to the Homes UK conference, John Milner of Baily Garner presented the data on a number of housing projects undertaken in the social housing sector which placed the retrofit costs between £48,000 and £100,000 per property.
So, where does that the leave the average, self-funding householder?
For the project at the Farmhouse we are taking the approach of trialing a number of low cost, small measures and assessing the difference they can make. A quick scan of the property with a thermal camera showed us where the worst of the heat loss was happening. Unsurprisingly the single glazed windows in the old part of the house were the number one culprits. This is closely followed by the frames of windows and doors, both old and new, and the disused chimney stack.
Starting with the windows, a replacement with a proper double or triple glazed unit would of course be the ideal, but ruinously expensive solution. So, we are opting for a self-installed secondary system called Magneglaze. This involves the fitting of made to measure, thick PET panels which are held in place by super strong magnetic strips. They form a strong seal and so far results are promising. We have two adjacent attic rooms, one where we have installed the system and the other is left untreated. Our temperature readings show that there was a 2-3 degree temperature difference maintained overnight, and then during the day when one room began to be used, and small amount of heat went in, the heat retention was noticeable.
Working out at a little over £100 per window, this certainly seems like a good first step.
We are also addressing general draft proofing . It doesn’t have to be the sausage dog from the 1970s though! The old part of the house has an external door directly into the living room so the use of a thermal curtain across it is an immediate improvement. Checking and renewing window and door seals, and covering keyholes, is not revolutionary thinking, but each little step can cumulatively improve the thermal envelope.
The chimney stack is a potentially tricky one to overcome. On close examination, the chimney appears to have been sealed at the top, and an air brick inserted. At the bottom, it has been sealed with a decorative cast iron fireplace with an iron sealing panel wedged at an angle, leaving a good 10cm gap. No wonder the heat disappears up there. The complicated thing about disused chimneys is to get the balance right between air flow and sealing. It is tempting to seal it completely but the salts from the accumulated residue in the chimney draw moisture, and without some ventilation will lead to damp in the walls. We have come across an interesting solution which we will be trialing; the delightfully named Chimney Sheep. This UK based company manufactures a flexible plug, made entirely from wool. Inserting this up into the chimney provides a thick insulating layer to prevent heat loss. It should still allow sufficient airflow to prevent wall damp developing. In the longer term we will be assessing whether it might be possible to cavity fill the chimney stack altogether but more on that later. In the meantime, the idea of having Shaun the Sheep stuck up the chimney this Christmas sounds intriguing and I am assured that Father Christmas can still make his visit.