While almost everyone has a heater of some sort in their home, it’s fairly unlikely that the heat provided by a central heating system such as a furnace is distributed in an efficient way. There’s little reason to heat bedrooms during the day, or a kitchen during the night, but heating systems tend to heat whole living space regardless of the time of day or the amount of use. You can solve this problem, like most problems, with an Arduino.
[Karl]’s build uses a series of radiator valves to control when each room gets heat from a boiler. The valves, with a temperature monitor at each valve, are tied into a central Arduino Mega using alarm wiring. By knowing the time of day and the desired temperature in each room, the Arduino can control when heat is applied to each room and when it is shut off, presumably making the entire system much more efficient. It also has control over the circulating pump and some of the other boiler equipment.
Presumably this type of system could be adapted to a system which uses a furnace and an air handler as well, although it is not quite as straightforward to close vents off using a central unit like this as it is to work with a boiler like [Karl] has. With careful design, though, it could be done. Besides replacing thermostats, we can’t say we’ve ever seen this done before.
Thanks to [SMS] for the tip!
For forced air systems…. There were some thermo controlled vents, standalone, battery powered, around at the discount and higher priced dollars stores ($4 here) They were absolutely useless of course, because of temperature soaking of the sensor at the vent, but did give you the neatly moulded standard vent with a solenoid actuator. Now you could either put the smarts inside with a remote temperature sensor or control system or wire them to remote smarts with a remote temperature sensor or timer.
Dammit, 3 old fart moments in 24 hours LOL… Conflated two different things I have, a thermo controlled one, I think I picked up at a yard sale, and the one that was in the dollar/discount stores was the Vent-Miser ..
https://www.amazon.com/Vent-Miser-91664-Programmable-Energy-Inches/dp/B000MWBPKA?th=1
Which you’ll note has a programmable timer, and is discontinued, which is probably why come it appeared in those types of stores. Fits a 4″ x 10″ hole. However, same kinda thing, actuated vent that you can have your wicked way with, potentially cheap if you can find any locally.
Don’t sweat it, buddy, I can have more than 3 at 73! Thanks for the link. I’ll look for it in South Carolina.
That looks like it has a pretty significant area taken up by the UI where an ordinary vent cover has more holes. It seems like even when it’s open it would be restricting the airlflow!
One way to avoid batteries is run silicone insulated low voltage wiring through the heating ducts themselves. That way you can pack a baffle, actuator, and brains inside the vent at each vent. No mess, no ugliness, much more robust against getting hit by a roomba/kid/pet. Communicate via wifi or wired to the control system, and, yeah, separate temp sensors in each room. (Or, arguably, no need for that, as above: you just don’t heat anything but bedrooms at night and rely on the standard whole house thermometer to determine when that happens.)
Anything you run through an air vent needs to be plenum rated, same as if it was in office ceiling space. In case of a fire, you really don’t want stuff burning in your vents that will make your lungs unhappy.
Yea, just use enough plenum rated CAT cable to be capable of the amperage if you want to use something readily at hand. Although I imagine 22 gauge primary wire, plenum rated, isn’t that expensive.
Don’t let a code official/home inspector catch you doing that.
It’s a zoned system. Commonly available, but pretty much a case of you get what you pay for, and most people (or builders) chose not to see the benefit of shelling out an extra few hundred dollars per room or zone when they put in a new heating & cooling system.
It’s not like you install one of these things for comfort — it’s strictly a cost saving measure. But even in my drafty 80-year-old house it would be unlikely to see reasonable payback period on the capital expense (we spent around $500 on heating & air conditioning last year).
$500 will buy plenty of servos, microcontrollers, PIR sensors, and material to make butterfly valves out of.
What’s the point buying all that? Their house need an insulation more that controlled vents.
First off, if you spend $500 on HVAC costs in a year, that’s fairly cheap. In the US it’s typically a fair amount more than that, and obviously the larger the home, the bigger the cost.
But even at $500, zoned systems tend to reduce energy consumption typically around 20% in controlled testing in scientific literature. Which means you’re talking about a $100 savings per year. This system wouldn’t even cost that.
When had our furnace replaced 5 years ago we asked the installer to quote on modifying the ductwork (to code, mind you) with remote-controlled dampers to accommodate zoned control. Answer: $3000, more than the $2800 (dual-stage 93% efficient) furnace. That kiboshed that idea. Sure, it’s an old house with a lot of labor required to make the changes, but still an indication of the work involved.
Sure, you can go cheap and bodge something that can sort of work for a while. You can spend hours and hours designing and building and tweaking and changing. Is it to code? Would it pass an inspection? Would it even survive a building permit application (required for ductwork modifications, here). Are you going to have something you can reliably and legally pass on to the next homeowner?
Cheap, half-ass, unreliable, questionably-engineered solutions might be fun to play with, but have no place in a critical house system. Not when my family is subject to its whims and failure modes.
Aside: Those furnace installers also warned that you couldn’t just adjust dampers willy-nilly, because the furnace requires a certain range of airflow to keep its temperature rise in the correct zone: It was a common failure mode in natural-draft furnaces to have a cracked heat exchanger through overheating because of blocked vents or clogged filters — the exhaust gasses could then enter the home. Modern draft-induced high efficiency furnaces pull a negative pressure in the heat exchanger so it’s not the hazard it used to be, but it’s still important to make sure the airflow stays correct so the high efficiency furnace’s condensing heat exchangers have the correct temperature profile to work as designed.
We have a hydronic system (hot water and rads) in our house, and zone control has been pretty common with such systems for some time now. One can have one pump pushing hot water into a solenoid-controlled distribution system similar to the linked project, but it’s a bit more elegant to have a primary loop with the boiler, and secondary pumps driving each separate zone. We have 3 zones, and currently we are just using cheap programmable thermostats so that the temperature in unoccupied areas is allowed to drop.
Perhaps in future I’ll look into more complex control systems. So many projects…
Working on adding an attic fan controlled by Arduino, a couple dht22’s with ifttt capabilities to combat condensation in the winter and keeping the AC running less spring and fall.
Please publish! Paula said she spent $500 in heating/cooling last year. Not sure where she lives. A drop in the bucket. Stayed in a big ‘ol historic house and paid $1,500 one month for heat. Bought a smaller, newer home, but I’m itching to put a fan in the attic to reduce cost. Please publish!
Not far from Detroit. 1500 sq. ft. 4 bedroom 2.5 storey. 80 years old. Uninsulated brick walls, R20 in the attic. A/C runs 20-100 hours/year depending on the summer (has not run yet this year). 60,000 BTU/hr gas furnace runs 25% duty cycle on a cold winter night, 50% if it’s really windy. Costs are low because gas is cheap. It used to be an electric furnace, 3x the cost.
Many forced air furances can be damaged by closing off vents in too many places at once. It increases the pressure , works the fan harder, etc. It may be a good idea to check if your furnace is able to deal with closed off outlets before installing such a system
I’m not very familiar with air furnaces but couldn’t this issue be mitigated by having the controller maintain a minimum number of vents open?
The problem is that its like 70%+ usually unless you could manage to rig some sort of relief vent. (Maybe one extra large vent)
I’m just happy to see a project that uses on of the many readily available and cost effective junction boxes rather than some custom PLA enclosure. I see project after project where hours of printing time went into creating a rectangular box with no greater functionality or aesthetic value than the commercially available offerings (not to mention way less thermal stability). If someone wants to hone their skills with 3D printing with a simple enclosure or go for a certain aesthetic I have no issue with that. I do have to wonder, however, how many fascinating projects have been bogged down by enclosure design rather than opting for a $4 PVC junction box from the hardware store.
Never seen this done before? Really? There are loads of intelligent TRV systems on the market, and even an open source one https://github.com/opentrv
I picked up some programmable TRV’s on eBay for around £7 each, and they work pretty well, main advantage is that the room temperature is more accurately controlled, but secondly controlled by time of day. Great in the bedroom where you want it cooler for a good night’s sleep but to warm up in the morning just before you get up.
IRL you won’t gain much lowering the temperature in rooms your not in.
It will require more energy heating it back up again.
And consider you add about 100w of heat per person that your in you would gain more lowering the heat in a room your visiting.
Specially if you are a number of people in the same room.
That’s not how heat loss works. If you have a leaky bucket, you don’t pour water into it all the time until you need a full bucket of water. You want to warm the room so that it reaches your desired temperature by the time you use it
And I can’t understand your second paragraph.
For a long time I have been dreaming of building a system of dampers and temperature sensors for each room and also sort of a damper/fan combo that would be shut in each window with a charlie bar. I would have some sort of rain and temperature sensors outside or maybe just scrape the weather from internet. Either way I would definitely get the pollen count from the internet. The whole system would then decide when to run the furnace or A/C, which rooms to run it into and when to blow air in or out which windows automatically.
Maybe when I retire.
I cut my forced air furnace gas consumption by 33% without lowering the setpoint temperature by just by modifying how the thermostat works. Now it’s either on for a long time or off for a long time rather than many short cycles.
https://hackaday.io/project/172151-home-automation-with-nodemcu
Is your furnace oversized? I wouldn’t expect so many short run cycles unless it really puts out some heat for the space. I would be surprised if mine ever ran less than 30 minutes when it kicks on… I have been looking a integrating some at least reporting of my ACs into home assistant so may steal some of these ideas – thanks!
This article and others like it are for people who either can’t afford or refuse to research minisplit systems which can save you 80%.