Wednesday 22 June 2022

Cool!

Have you noticed how the nights are drawing in?

For a number of months I've been considering buying and installing an air-conditioning system to use upstairs in the house which, due to a design fault on my part, gets hideously hot during heatwaves, which seem to be on the increase.

The upstairs windows, which are long and narrow at both ends of the house, open from the bottom, hinging from the top, and only open about 6 inches. This means there's little scope for letting hot air out of the bedroom, which comprises the entire upstairs. Additionally, we have a vaulted ceiling, which also captures the hot air as it rises and retains it  it has nowhere to escape.

We do have one, small, side-opening window, but it's no higher than waist height, so doesn't do much to let the heat out.

There's a couple of structural solutions:

  • Change the hinges on the long, tall windows so they open at the top, rather than the bottom,
  • Put a Velux window in the roof, through which the heat can escape naturally. 
Both are quite expensive and moving the hinges on the long, tall windows won't do that much due to their restricted opening, which is because of their weight.

I've been keeping an eye out for a 2nd hand, wall mounted aircon with sufficient oomph to cater for the huge volume, but have so far been unsuccessful. 

However, as luck would have it, I called in at a local car dealership that my colleague and I buy cars for. They were having a refurbishment of the customer area and were getting rid of a De Longhi, mobile aircon unit. I took possession of it for free.


Given we only have a few really hot days a year, a wall mounted unit would be overkill, but a mobile on this size is perfect, especially when it costs nothing. When not required, it can be stored in my (as yet unfinished) workshop.

It does still have a problem, in that the duct for the hot air has to be vented outside. The usual way of doing this with a mobile unit is to hang the hose out of a window, which is not very efficient due to the gaps. I have a couple of options:

  1. Insert a permanent exit vent into the wall of the house, or
  2. Tap a vent into the wood burner's stainless steel chimney, which passes through the bedroom.

Tapping into the chimney vent would be the cheapest. The vent would need to be capable of being sealed off when not in use, as we don't want wood smoke in the bedroom, not that we ever use the wood burner, except in an emergency. You can get inspection hatches, used for when sweeping the chimney and, with a bit of modification, that would seem the best solution. The hot air could then vent naturally up the stainless steel pipe.

There are polythene window covers you can get, but they look rather flimsy and faffy to me.

There is one other, very cheap solution - a simple, cardboard sheet over the small window with a hole cut into it for the heat pipe. Not elegant, but simple and effective for the week or so of really hot weather. I tried it and it works.


However, I've ordered a sheet of 1m x 60cm x 3mm acrylic, which I will pin to the window aperture with clips, cutting a suitable hole into for the vent pipe. It can be easily mounted and dismounted and will be virtually hermetically sealed.


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