10.12.2022 Blowing hot and cold.

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 Saturday 10th 0C/31F. Up at 6.45. 17C/62F upstairs. 14C/57F in the lounge. 10C/50F in the kitchen. 6C/43F in the bathroom. My British fiend has pointed out that I ought to check the insulation in the downstairs walls. To which end I shall use my pistol thermometer to monitor wall temperatures. 

 

 Particularly in the lounge. Where the north wall shows signs of polyurethane insulation. With open gaps between the boards and covering plasterboard. The longest, external, east wall is uninsulated behind the bricks. 

 

 The south wall is protected, to some degree, by the lean-to greenhouse. The greenhouse is not well sealed and cannot be. Not without major and expensive replacement of all the rubber/glass seals and rounded plastic shoulder plates. 

 

 The single sheets of roofing glass slowly slide down the gently sloping rafters over time. Which pushes the plastic shoulders away from the curved supporting profiles. As the greenhouse is single glazed I doubt that I can improve its thermal performance myself. Had I the foresight, 20 years ago, I would have siliconed the roofing sheets to the roof's metal framework. 

 

 This would also have avoided some drips around the opening skylights. Which have never been used. Since they offered no detectable reduction in summer temperatures. Despite the double, sliding doors, at both ends, also being wide open. Temperatures were often well over 100F in the greenhouse during summer months. Sadly it rarely provided any heat to the house in cooler/colder weather. 

 

 Our attempts to shade the greenhouse with conifers never worked. Except to make it incredibly dark in winter. I have since cut them down. To allow the sun to reach the greenhouse unhindered in spring and autumn.

 

 I put up the 22'x8' double length greenhouse in the completely false hope of adding winter warmth. Or even the false dream of somewhere nice to sit "outside" but sheltered. It was never ever used as such. The harsh environment out there being completely intolerable for the vast majority of the time.

 

  If you are ever tempted to believe the seller's completely false hype and spend your own money: I would strongly suggest you visit lots of open air displays of greenhouses for a severe does of harsh [commercial] reality! Sub-zero freezing cold or desert hot. Depending on when you go. 

 

 If you just want somewhere to grow tomatoes then you may be on slightly safer ground. Provided you buy proper shade net. Not the obscenely overpriced crap they sell at the dealers. Made from children's pool fishing nets for the seaside! The internal [short lived] white shading material, we used, had almost no effect on internal temperatures. Except to slightly reduce the glare from the sun. 

 

 Only the recent addition of professional quality, green shade netting OUTSIDE THE GLASS has ever helped. Though even this requires open doors both ends and a helpful through draught on hotter days. The shade netting made the greenhouse a pleasant place to be for the very first time in two decades.

 

 Even then it required two layers of grower's quality shade net. Which I reduced to one layer as the summer heat eased off. Now removed altogether to hopefully extend its life over the winter. 

 

 It also allows every drop of the low winter sun to reach inside the greenhouse. And, even more importantly, on into the house for more light. I enjoyed low winter sunshine through the lounge windows the other day. For the first time in two decades. It was amazing!

 

 The shade netting came in a huge and heavy roll from a dealer on eBay[DE]. It has pierced hems so that cords can be threaded through the edges to jeep it in place on sloping roofs.  The picture was taken by my wife during Covid. As I patiently threaded a strong cord through the holes provided in the edge of the net. My hair wasn't trimmed for 18 months! This quality of shade netting has been a revelation! One which I wish my dear wife had enjoyed. 

 8.00 Finally light enough to see the trees and the thin layer of new snow. 

 

 9.45 After lighting the stove I set of on a later walk than usual. White smoke was rising vertically from the chimney as I looked back. It was difficult to be sure whether the roads had been salted today. There were long stretches of white snow near the verge and frozen slush in stripes. Even the darkest strips were quite slippery under the soles of my walking boots.

 

 The road showed long cracks. Which hadn't been there before. Finding somewhere safe to walk became even worse in the lanes. With only narrow sections of still slippery, darker asphalt on the heavily cambered surface. Several cars caused me to take to the verges. I didn't want to force them to change course.

 

 A bird of prey clung to a spindly birch. It shuffled, but was obviously too tired, hungry or cold. To move away as I passed. Small groups of birds flew further along along the mature, roadside hedgerows as I progressed. Keeping their distance, but pausing to pick at morsels amongst the branches.

The logs from the last trailer load are coming in from the greenhouse at between 16% and 22% moisture content. Having them in the room for a day. Should help to reduce the moisture content before they go into the stove. Some of them are spitting as they catch fire. Presumably caused by pockets of moisture. 

 11.00 Sunshine! Albeit it from a low sun through broken cloud. The greenhouse is at 47F. Compared to 32C outside. So it is certainly providing some warmth to the exterior of the house wall. I have just been out to clear the snow from the greenhouse roof. To allow maximum access for the sunlight to reach the southern wall and scattered contents. I also cut down the last of the conifers. It cast a large shadow on the greenhouse.

 

 Without added absorption surfaces there is only very little warming of the house wall. I have plans for using empty cans sprayed black, as solar absorbers. Whether they would work, in winter sun and without additional glazing, is another matter. The greenhouse glass would provide some benefit but how much? 

 

 Normally, the heated metal surfaces would cause convection currents to carry the heat upwards in a closed box with a glazed front. A fan, or large vent, would allow the accumulated heat at the top to be brought indoors. The cooler, indoor air is then allowed to enter the bottom of the solar panel. To be re-circulated continuously. 

 

 Would black painted cans, mounted on a plywood backboard, help to warm the greenhouse in winter? I have no idea. A black, plastic meat tray was at 30C locally. Suggesting that black painted tins would have a useful heating effect. The panels must be easily removable, or easily covered, to avoid added summer heating.

 

 Out in the greenhouse, the white painted house wall had a vertical, temperature gradient. In weak sunshine it ranged from 8C near the bottom. To 28C near the top. Where the greenhouse roof is fixed to the house wall. The air temperature [low down in the shade] reads 10C or 50F! Well above the 0C/32F of the great outdoors!

 

 Indoors, in the lounge, the gradient was from 8C near the floor. To 15C near the ceiling. The room temperature is about 15C or 60F. There were distinct cold spots where the insulated plasterboard on  the north wall has gaps. Bringing the remote reading thermometer closer caused the reading to drop from 15C to 10C. This is probably causing a cold bridge. Spray foam could close the larger gaps. Removal of one insulated panel might offer a clue as to the state of the wall behind.

 15.30 I had to go grocery shopping. It was already dark on my way home. The roads were almost clear. With patches of slush and snow here and there. Particularly in the woods. 

 19.30 0C/30F. Dinner was [perfect] poached eggs on toast. Followed by tomato soup and a bread roll.

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