Thermo Differential thermostat

Hi

I’m disabled & live in an unheated rented bungalow. As an experiment I want to harness the wasted heat in my attic & duct it to my living space.

After doing a bit of research, it looks like I’ll need a thermometer that differentiates between two given points (Attic & lounge) then - as long as it’s warmer in the attic than the ground floor, turn on the system.

Some people have suggested that I use two stats & set the lounge one at a lower temp than the attic one, but this narrows down the starting point - temp-wise - which would probably be different every day.

I need something that will just differentiate between the two points at any temperature.

My budget is limited, so need to watch what I spend on this. If it works, then I can upgrade later, but for the time being, economy is the watchword.

I’ve built a few Velleman items as well as some of my own LED lights & controllers, so as long as the items arn’t too small I should be able to make my own if necessary.

Any ideas out there please ?

PS: I e-mailed Velleman about it, but they suggest that I use the forum.

MODS: if this is in the wrong section - please feel free to move it - thanks

At this time, we do not carry such a device.
Might be a good idea to add such an item to our range of products in the future.

Thanks for getting back.
With my limited knowledge of these things, I don’t imagine it would be a difficult thing to produce.

In the mean time, any idea how I might get over my problem ?

Somewhere in the back of my mind, I think that 2 x ‘stats might work (tho’ not to my required level - but somewhere to start) in a sort of “2-way lighting switch” logic ?!


I have seen one of your 'stats with a short 'sensor' on it,,,,,, would it be possible to replace this with a thermister, on say a 2 meter lead ? (incidentally, is that 'sensor actually a thermister anyway ?)

Any help or advice - from anywhere - would be appreciated.

thanks for reading this.

What you are seeking is a differential thermostat, they are quite common in solar heating systems.

Here’s a link to a simple unit for $75US, here’s a commercial device for $89US.

Search Google for “differential thermostat” and you’ll find many more…

many thanks Cliff.
I like the idea of the basic - bare bones - kit in your first link. I’ve dropped them a line for more details.

As I’m in the U.K they may not export to us - never mind, I should be able to find something similar over here, now I know what I’m looking for.

thanks again