Piwoslaw's conservation thread

[Daox]

Your HDD were exactly the same for both years or is that a typo? Congrats on an 11% decrease though, thats really good!

Also, your electric usage image isn't working.

[Piwoslaw]

Thanks, that was a typo. Everything should be fixed now.

[Piwoslaw]

Summer is now officially over! Yesterday was the last warm day (actually, over 20°C/68°F in October is an anomoly), today it's under 10°C/50°F and it's raining for the first time in what seems like months The rain barrels are slowly filling up and I plan to keep them deployed until freezing temperatures come.

Of course, the change in weather also means that the heating system will need to be fired up soon. Last year we had to start heating in the first half of September. This year I got a few things done, or nearly done, to slightly increase the system efficiency:

• For the first time in at least 4-5 years I cleaned the boiler's heat exchanger with a brush and vacuum cleaner. Lots of dust and grime between the fins. I also cleaned out the circulation pump's filter, now it's quieter.
• I got a thermal switch to keep the circulation pump on for a few minutes after the boiler turns off, allowing more heat to be distributed to the house.
• I've installed a radiant barrier (3mm styrofoam with alu foil on one side) behind the radiators to reflect heat back into the room, instead of the cold wall.
  
  
  That's the same stuff I used to increase the refrigerator's efficiency.
• I've collected a few 12cm computer fans to mount under the radiators, and a 12V 1200mA wall wart to power them. Once installed, they should help lower the heating system's temperature, distribute the heat better, and shorten on time, reducing power consumption.
• I bought foam insulation for the heating system's pipes going through the unheated basement. Most of the supply pipes were insulated by my Dad-in-law many years ago, but not all of them, and the returns are bare. I'm waiting with this until we start heating so that I can check before/after tempertures to see how much of a difference the insulation made. Dad-in-law told me that the returns shouldn't be insulated because they keep the basement from freezing - it is very drafty and gets as cold as 4-5°C/39-41°F during the later half of winter. I may only insulate the remaining supply pipes and wait with the returns until the basement gets sealed, maybe even insulated, which won't happen while the boiler sucks lots of air. Feeding it through a pipe with a damper may be next year's project.
• During the coldest months the draft from under the basement door is as cold, and as strong, as from an A/C. Since all that cold air in the heated part of the house is not good, I replaced the basement door with one that will stop that draft. The old door was made from a bunch of boards about 40 years ago and had cracks big enough to put a finger into The new door is already doing its thing - there is a noticeable 2-3 degree difference when entering the basement, and we're not even heating yet!
• The door is only half of the problem - there is a window next to the stairs which allows cold air from the basement to be sucked upstairs. I'd like to cover that with a piece of clear plastic and seal the edges. Still on the to-do list, but has high priority as it's getting cold.
  
  
• I made removeable window insect screens, which allowed me to remove the screens that were mounted in a more or less permanent way. This let more light into the house
• I also cleaned all the windows, which actually let more light in than removing the screens Shows how dirty I let them become, but I decided that's OK during summer, the dirt keeps some sunshine/heat out.

[Daox]

Hah, looking back it sure seems like you did a lot of improvements! Funny how it all adds up.

[Piwoslaw]

I've been monitoring how the boiler works recently with the Arduino data logger. Here is a graph of temperatures, logged every minute for the last 8 days (temps are °C):



The red and yellow are supply and return water temperature at the boiler, cyan is room temperature (sensor is next to thermostat), blue is outdoor temperature. I'm still calibrating the sensors (readings from supply and return are much too low, room shows 1.5°C too low, outdoor 3°C too high) but I can see a pattern in how the boiler cycles on and off.

At night (21:00-09:00) the t-stat turns on at 16°C and off at 17°C, during the day (09:00-21:00) 17.25°C and 18.25°C, resp. When I'm at home I keep the t-stat in night mode, warming up to day temps around 19:00 when everyone is home (and ready to complain).

The wife and I were gone for three days and Dad-in-law didn't fiddle with the t-stat, so those three days saw a higher temperature, which means that the boiler turned on more often (spikes in graph closer together).

Another thing which can be noticed on the graph is that when the t-stat is in night mode for most of the day, then the system's water temperature sees lower temperatures, which means that the boiler works more efficiently (cold water = larger temperature difference = more heat can be absorbed).

I've decided to reprogram the t-stat to do what I've been doing manually, ie stay night temperature for most of the day, warming up only between 19:00-21:00. I'll see how many complaints I get...

[Piwoslaw]

Small update on a few of the renovations I mentioned earlier. The end of 2011 and the first half of January 2012 much warmer than average, so it's hard to tell if they've had an effect on gas usage and if so, how much.

Originally Posted by Piwoslaw

• I got a thermal switch to keep the circulation pump on for a few minutes after the boiler turns off, allowing more heat to be distributed to the house.

The pump stays on for about 40-60 minutes after the boiler goes off, which causes the livingroom temperature to rise another 0.2-0.3°C after the thermostat clicks.

Originally Posted by Piwoslaw

• I've collected a few 12cm computer fans to mount under the radiators, and a 12V 1200mA wall wart to power them. Once installed, they should help lower the heating system's temperature, distribute the heat better, and shorten on time, reducing power consumption.

After 2 months the fans may help with distributing warm air in each room, but I doubt that they really make a dent in the amount of heat actually getting transfered: The fans don't really move too much air (I wanted to keep them quiet), while the cast iron radiators are large and there is a lot of water (~250-300 liters) in the system. Well, it's still a net win

Originally Posted by Piwoslaw

• During the coldest months the draft from under the basement door is as cold, and as strong, as from an A/C. Since all that cold air in the heated part of the house is not good, I replaced the basement door with one that will stop that draft. The old door was made from a bunch of boards about 40 years ago and had cracks big enough to put a finger into The new door is already doing its thing - there is a noticeable 2-3 degree difference when entering the basement, and we're not even heating yet!
• The door is only half of the problem - there is a window next to the stairs which allows cold air from the basement to be sucked upstairs. I'd like to cover that with a piece of clear plastic and seal the edges. Still on the to-do list, but has high priority as it's getting cold.
  
  

With the new door and sealed window there is now hardly any cold air coming up from the basement. Still a few small holes and cracks here and there, but the airflow is at least an order of magnitude weaker. One of the side effects, though, is that there is also less air being sucked from the upstairs rooms to the ventilation shafts. This means that the house is losing less heat, but also there is less ventilation and more humidity build-up. Sometimes cold air actually comes in through those shafts, which never happened during previous winters.

[Piwoslaw]

We are in the middle of the coldest week of the year right now, daytime temperatures here are between -16° and -12°C (3° to 10°F), while at night it's as low as -22°C (-8°F). With the temperature difference between in and out this big I decided this is a great chance to see where I'm losing the most heat (or gaining the most cold, since I didn't want to go outside). Armed with my IR thermometer I checked the floors and walls in each room, giving special attention to windows. I made separate measurements for partition walls and outer walls, while the temperture of the window frame was measured on both sides (indoor and outdoor).

I measured the same spots that I checked during the hottest day of last summer (33°C/92°F), now I need to compare the data and see where to focus the next renovations.

Among the interesting things I noticed was heat loss through the front door: It is made out of 5 panels (coffers) and has a narrow window in the middle.

The panels are thicker in the middle and the temperature there and on the frame between panels was 5.5°C (42°F), but the thinner panel edges were only 2.5°C (66.5°F). The window was 2°C (35.5°F). I'll add that the temperature of the little entrance hallway was around 11°C (52°F).
On the outside of the door (outdoor temp -22°C/-8°F), the panels' temperature was between -19° and -13°C (-2° to 8.5°F) while the window was -13°C (8.5°F). So I'm losing some heat through the front door, especially through the window, which is already double pane. Insulating it like my brother-in-law did would help, but I'd have to cover the window. We very much need that little window, both for the light it gives in the dark hallway, and to see our entrance gate. I might be possible to cut a hole in the insulation to leave the window, but that would only partially solve the problem.

My Grandma's house has a double front door, actually two doors on one frame, one opens in, the other out. That is quite common in Poland and seems to work quite well, but in our little hallway there just isn't enough room for the door to open inwards. I also though about adding an extra pane of glass to the window, but I doubt that would look even half nice if I did it myself

[Piwoslaw]

With the heat wave (30°C/86°F) that everyone here seems to appreciate, heating season 2011/12 is officially over I summed up some data to see how we did this winter, compared to the previous two seasons for which I have data. As a comparison, I've added our cousin's gas usage (she lives next door). Her usage is much larger than ours since she has a larger house, though it's hard to explain why her gas usage has been going up even though each winter has been slightly warmer than the previous. I'll add that the gas usage includes cooking and hot water (~0.5 m3 per day).

Oct 1-May 1	winter 2009-2010	winter 2010-2011	winter 2011-2012
HDD (15.5°C)	2931	2848.4	2738.5
our gas usage m3 (therms)	1835 (668)	1631 (594)	1401 (510)
cousin's gas usage m3 (therms)	2435 (887)	2532 (922)	2594 (945)

To measure the efficiency of heating between seasons I look at the gas used per HDD.

Oct 1-May 1	winter 2009-2010	winter 2010-2011	winter 2011-2012
our gas usage efficiency (m3 per HDD)	0.63	0.57	0.51
cousin's gas usage efficiency (m3 per HDD)	0.83	0.89	0.95

As you can see, our cousin's heating efficiency over three heating seasons has dropped by almost 15%! I'll have to talk to her about it. On the other hand, I've been able to reduce our gas needs by 20% I think that's pretty good for a few small mods and aggresive use of the thermostat's controls (among other things: lowering the temperature a bit and seeing how cold it can get when nobody's at home).

[Daox]

Very nice reductions Piwoslaw! Any words of wisdom or key changes you made that you think got you most of the way there?

[Piwoslaw]

Just the stuff mentioned earlier on this page. Sealing off the cold air coming up from the basement made a noticible (though unquantified) difference, as did the extended running of the boiler's circulation pump and putting fans under the radiators (worth ~13% during the coldest days).

I think that just keeping my hand on the t-stat and telling everyone to dress warmer (even warmer!) also scored a few points, though maybe not with my housemates

I don't want to take all the credit, though. I have no data to confirm this, but I think we had more sunny days this winter, which had some effect on the temperature in the room with the thermostat. On the other hand, our cousin's house also gets some solar gain during the winter, so she should have also seen a decrease in gas usage, which she didn't.