In the former Soviet Union we just have central heating The government maintains indoor temperature at 24 degrees from October to May, and the water is heated at the power stations.
And a €500 heating bill every month.
Attacking My Landlord's Boiler
211–220 of 232 posts
Re: Attacking My Landlord's Boiler
#212Earlier quoted context omitted.
> the theory being that warming up a cold house in the morning costs more energy than maintaining a stable temperature This is only true if the heating happens quickly and the system is less efficient when heating quickly. Otherwise, this doesn't make sense from a physics standpoint. A temporarily lower temperature differential means less kWh of heat lost.
This is a whole research topic, my PhD in fact! FWIW I run my heat pump intermittently and with locally-smart TRVs that get to call for heat centrally, and a weather compensation only flow temperature curve, and it WORKSFORME! https://www.earth.org.uk/heat-pump-16WW-control.html
Fascinating read.
Certainly feels like I'd need PhD from it to successfully install, modify, calibrate and run the installation until its fully adjusted, for the peak comfort and minimum cost/dirty energy use.
Re: Attacking My Landlord's Boiler
#213I wonder what the ideal one-size fits all thermostat looks like. The one in my apartment has a “feature” a lot of US thermostats now have, where you set four ordered times called wake, leave, return, and sleep and the temperature you want the space in each interval. I know very few people who actually live in a household where everyone wakes, leaves, returns, and sleeps on the same schedule every day. I work from hom…
My wife and I worked a six-week shift work schedule for a long time. We got second-gen nest thermostats when they first came out (2012) thinking they were neat. Nope! The smart learning feature was the biggest pain in the ass. You’d be sleeping during the day for a night shift, only to find yourself freezing because it decided no one was home.
Mine works OK as long as presence detection (using people's phones and Google Home) is operating correctly.
Everyone leaves, and the thermostat adjusts.
Someone comes home (or walks in front of it), and it goes back to the normal setpoint.
Sounds easy. Isn't always easy.
The reliability of this seems to be highly dependent on the phone(s) themselves simply succeeding at not killing useful processes.
Overall, I'm not entirely displeased with it. I procured it very inexpensively by buying it from one of my energy provider's online store in conjunction with a substantial rebate from my other energy provider. I'm confident that it paid for itself very quickly, and it's nice to be able to set the thermostat remotely.
My lament is that there seems to be approximately nothing I can do to improve the presence detection function without gymnastics or spending real money. What I want is a local API that I can enable and do stuff with; what I get is "Good luck! Have you tried buying Nest Protect subscription motion detectors? (Oh lol, we stopped selling those.)"
(I'm OK with the privacy and security aspects of what I'm trying to do. I'm not OK with having a connected device that I can't bend to my will. I'm even less OK with more recurring expenses. The next thermostat I buy will have local control over the LAN, but it probably won't pay for itself quite as quickly as this one did.)
[note: I've never played with the auto-schedule "learning" function at all. It always seemed like a complete waste of time, since I for one do not have a regular schedule.]
Re: Attacking My Landlord's Boiler
#214Earlier quoted context omitted.
First, sooner or later you have to replace your furnace with a heat pump. Second, modern furnaceses are condensing. Return temp should be as low as possible maximise condensing.
We agree return temps should be lower, but to determine how critical this is you need to out numbers on that. In steady state operation at maximum load a difference in return temperatures of 15f is ~1% efficiency. But steady state at maximum load is an extreme situation the average return temperature is well below that theoretical maximum thus an even wider difference is needed for a seasonal difference of 1%. Redund…
As said, at some point you will likely replace your furnace by a heat pump. Then all investment to low temperatures will pay off. A modern gas furnace is no backup for a heat pump, as it also needs electricity. I would recommend a low tech solution like a wood stove for backup. I have one in my cellar. In case of a long power outage I would likely just install this through some open window and do some redneck stuff to make it airtight.
Re: Attacking My Landlord's Boiler
#215I would have put a peltier/TEC below the thermostat to influence it's measured air temp vs resorting to reverse engineering and illegal signal broadcasting.
If I understood the OP correctly, then the broadcasting would only be illegal in the US.
Yes but no: The original device operates in the 868MHz band, which is a ISM band in the EU. However this band isn't availabe for public use in the US (IIRC some mobile phone cells operate in that band) - so the original thermostat is already illegal to sell/buy/use in the US.
If you bought such a thermostat in the US (e.g. at walmart or what-do-I-know), that device would probably operate on 433 or 915 MHz. I think you can legally broadcast on these in the US, much like the OP did [in the UK]. Power limits might be a bit different and such. But IANAL and no US person, so do some research before grabbing a HackRF One ;-)
Re: Attacking My Landlord's Boiler
#216Earlier quoted context omitted.
For every John Siegenthaler and Dan Holohan, there are thousands of mechanical engineers and tens of thousands of plumbers who are happier to slap in a $20K 4-hour boiler retrofit. There’s not enough extra money in catering to the 0.1% of homeowners who care about the details.
A lot of this is so easy with AI now. Just need some confidence and patience to work with AI lol.
It’s a service or human engineering problem rather than a mechanical engineering or knowledge problem.
Contractors today put in over-sized equipment, set flow temps higher than needed, undersize emitters for aesthetics and cost, and run pumps at full speed to avoid callbacks for “it’s too cold”. You can’t afford the windshield time to drive over to tweak the system to extract maximum performance, because homeowners don’t want to pay for it and will go with the lower bidder enough times that your premium AI-powered service will struggle.
I’ve tweaked my reset curve 12 times the first winter and 2 more times since then (counted from my spreadsheet).
Realistically, if I gave up on the last 3% tweaking, we could have lived with it after 2 post-install tweaks, but at least one of those had to wait for seriously cold weather snap to fine-tune the low end.
My spouse would happily agree that the house is finally very comfortable and noticeably more than before. She’d also tell friends who asked that there were a few days the first winter where the house wasn’t warm enough and needed an adjustment. People who heard that story might conclude that their neighbor’s guy who never has a callback for “too cold” is a safer bet.
Over time, I think even the best mechanical contractors will start to lean towards avoiding callbacks and do that by running the system 5-10°C hotter than “correct” engineering requires. That’s still better than today, where flow is set to 80°C, pumps to max, and the thermostat cycles 4 times an hour but the house is never too cold.
Re: Attacking My Landlord's Boiler
#217This is basically why companies like HeatWatch have 90% market share for NYC landlords
Re: Attacking My Landlord's Boiler
#218Earlier quoted context omitted.
We agree return temps should be lower, but to determine how critical this is you need to out numbers on that. In steady state operation at maximum load a difference in return temperatures of 15f is ~1% efficiency. But steady state at maximum load is an extreme situation the average return temperature is well below that theoretical maximum thus an even wider difference is needed for a seasonal difference of 1%. Redund…
As said, at some point you will likely replace your furnace by a heat pump. Then all investment to low temperatures will pay off. A modern gas furnace is no backup for a heat pump, as it also needs electricity. I would recommend a low tech solution like a wood stove for backup. I have one in my cellar. In case of a long power outage I would likely just install this through some open window and do some redneck stuff t…
Trusting in the power grid for both is obviously not redundant, but it’s cheaper to get independent power for a furnace than heat pumps. Actual redundancy means you want completely independent systems so you shouldn’t then use the same heat delivery loops/pumps/fans either.
Wood stoves require you to physically be home and are kind of a pain to use thus make a poor backup on their own, though a solid 2nd backup.
PS: Most areas are better off with solar thermal + heat pumps. Solar thermal however requires sunlight which not everyone gets in the depth of winter.
Re: Attacking My Landlord's Boiler
#219Earlier quoted context omitted.
In slightly cooler climates, the answer for sleep is to open windows. This works in much of Europe, even through summer. But of course, not really feasible in Atlanta or Phoenix. Nighttime temps are too warm.
Open windows in a city often means you are invinting in pollution, both air and noise.
Opening windows also helps to evacuate inner pollution coming from furnitures, wall paint, parquet and other chemicals...
Re: Attacking My Landlord's Boiler
#220Could the same radio be controlling other nearby boilers unintentionally?