UFH 8 zone Heatmiser System Under Floorboards

[AshleyH]

14 minutes ago, AliG said:

I doubt would be worth the cost and effort. The biggest driver of the times and costs of heating is going to be the insulation of the room. You do have a faster heat loss than most people on the forum, but considering this is not a  new build, I don't think it is surprisingly fast.

 

It would be useful to know that there is enough insulation in the floor. Looking at the expansion foam around the edges, did they lay a concrete floor then put the insulation panels on top of it? Having looked on Google they look like they might be low profile panels that would not really provide enough insulation on their own and would allow a lot of heat to leak into the ground and slow down the system.

 

They may have made this choice to maximise head height or to not alter the floor levels.

 

I would be surprised if the floor was not warm at the temperatures you are running with makes me wonder about the amount of insulation in the floor.

 

 

 

 

so basically the house was totally renovated, the concrete floor were left and they used insulation boards to run the UFH pipes in, tbh I don’t think they put any insulation underneath the boards? Not that I’m aware of anyway? Could be wrong? Then the floorboards, ply and finished floor. 
 

yes I remember them worry about head height so that’s a possibility! There’s no chance I can get the flooring up now to get insulation underneath the boards ?

[AliG]

That's probably the issue, it is recommended to have at least 100mm of PIR below UFH. People like UFH but it is not a great retrofit product. It works best in well insulated houses built with UFH in mind. But there's nothing we can do about that now.

 

By increasing the set back temperature you will stop it getting so cold and the house will heat up faster, simply by never starting from as cold a point. But this could increase your bills a bit if there is not enough insulation under the UFH. You would just have to try it and see.

 

Are you finding your gas bills unexpectedly high? How much gas are you using compared to the size of the house?

[AshleyH]

Got to be honest I don’t think the laid that first? Would the insulation board the pipes are run through do the same thing no? 
 

We did last winter when we left the set point constant, we’ll give it ago this winter see how we get on. I’ll keep an eye on how much gas usage we use going forward. 
 

Thanks for the info you’ve passed on it been great. 
 

I’ll keep you updated! 

[AliG]

The board does the same thing, but it is just not thick enough, so a lot of heat will be going into the concrete and the ground rather than the room.

 

Happy to help.

 

I just noticed something on your settings. You have Monday to Friday morning set as 20C. As the temperature doesn't normally get below 20C, according to the charts, the heating won't come on in the morning. It is coming on in the afternoon when it is set to 22.5.

 

I would try setting it to 22C in the mornings, 20C during the day and when you are in bed and 22 or 22.5C for after work. This way if it does get cold it will kick in to stop the temperature getting lower and so it will heat up faster. I would also look at setting different rooms differently. We have the kitchen at 22C, but the dining room at 20C as we are hardly ever in there. As your house cools down quickly, I would also set the switch off time no more than an hour before bed. Setting the Differential to 0.5c will also keep the temperature more consistent.

 

I spent ages setting up the heating in every single room in the house as they are all different depending on whether they are bedrooms or living rooms, how much use they get, what direction they face and what flooring they have. We have quite a few south facing rooms where the heating is switched off and never has to be used, we also have a couple of colder north facing rooms where the thermostat is set lower as the heating kicks in at a lower temperature and a room with the heating on feels warmer than one where it is off even if the temperature is lower. It looks like you have only one setting for all the rooms.

 

We have one thermostat on an outside wall and all the others are on inside walls which also makes a slight difference. In my last house where the insulation was poorer I had to set one thermostat 5C lower than the room temperature as it was on an outside walls that had a draughty cavity.

Edited October 3, 2020 by AliG

[Onoff]

Might be some Salus/Heatmiser info here:

 

 

[Temp]

I think it would be useful to know the flow an return temperatures on the problem loops after they have been trying to heat the room for an hour or two.

 

If there is too much wood above the pipes the return temperatures will be high.

 

If you know the flow rate and the flow an return temperatures you can calculate the power going into the floor (although working out where it's going after that I'd harder).

 

[AshleyH]

On 03/10/2020 at 22:08, AliG said:

The board does the same thing, but it is just not thick enough, so a lot of heat will be going into the concrete and the ground rather than the room.

 

Happy to help.

 

I just noticed something on your settings. You have Monday to Friday morning set as 20C. As the temperature doesn't normally get below 20C, according to the charts, the heating won't come on in the morning. It is coming on in the afternoon when it is set to 22.5.

 

I would try setting it to 22C in the mornings, 20C during the day and when you are in bed and 22 or 22.5C for after work. This way if it does get cold it will kick in to stop the temperature getting lower and so it will heat up faster. I would also look at setting different rooms differently. We have the kitchen at 22C, but the dining room at 20C as we are hardly ever in there. As your house cools down quickly, I would also set the switch off time no more than an hour before bed. Setting the Differential to 0.5c will also keep the temperature more consistent.

 

I spent ages setting up the heating in every single room in the house as they are all different depending on whether they are bedrooms or living rooms, how much use they get, what direction they face and what flooring they have. We have quite a few south facing rooms where the heating is switched off and never has to be used, we also have a couple of colder north facing rooms where the thermostat is set lower as the heating kicks in at a lower temperature and a room with the heating on feels warmer than one where it is off even if the temperature is lower. It looks like you have only one setting for all the rooms.

 

We have one thermostat on an outside wall and all the others are on inside walls which also makes a slight difference. In my last house where the insulation was poorer I had to set one thermostat 5C lower than the room temperature as it was on an outside walls that had a draughty cavity.

 

This is the spec from the supplier for the insulation boards? 
 

 

[AliG]

Thanks, unfortunately I think they can do any thickness between 20 and 150mm and suspect it will be the thinner ones that were used.

 

The reality is there is no taking the floor up now, so you just have to find a way to work with what you have there. You could maybe improve the roof insulation, but that is likely the only area that can be easily changed.