Ensuite quandary

[CC45]

Evening all.

 

Spent all day finishing off the master bedroom and on suite ready for 1st fix elec & heating - so spent quite a lot of time chewing on 'things'.

 

Bedroom will have rads, controlled by a room stat in the room.  Heat loss is calculated to be around 500w or ~ 16w/m2.  Not convinced I need rads at all but going to put them in just in case and for eventual resale.  MVHR to be installed.  This room is sorted but I have some queries about the ensuite.

 

Some basic details of the current plan regarding heating the ensuite.  Towel rad fed from a manifold (one for upstairs with another for the down stairs ufh), planning on hooking this up to its own room stat so the good lady can run this room warmer / in summer, the other option would be to put an electric heating element in it for drying towels in summer.  With MVHR not 100% sure this isn't going OTT.  With tiles going down on the floor then we are also going to put electric ufh in but with a heat loss of around 100w any system we put in will be plenty warm enough.  

 

So am I going ott or just making sure the domestic services department is kept happy?  Suspect the extra cost isn't that much (doing it all myself) so any thoughts?

 

Thanks in advance,

 

CC

[Nickfromwales]

Deffo go for the electric element in the towel rad over wet plumbing it. That way you don't have to have the entire pumped warm water system going for just a trickle of heat to the one rad. 

After that it sounds your ok, as it's far easier to use electric solutions here vs wet warm water systems as the cost and complexity soon becomes significant. 

Using very good room stats which won't have too big an overshoot ( good hysteresis ) will be vital. @JSHarris may be able to provide a link to his which, iirc, switch at 0.1oC increments. 

[jack]

If you're already having UFH, perhaps just wire for a towel rail but don't install it unless you find you need it?

[Triassic]

I'd second what Nick said, electric towel rail, I've just fitted one and it's great.

 

if you question the need for rads, why not just fit the pipework (maybe hidden in the wall) and not the rads. See what the temperatures like and only buy the rads if needed.

[Jeremy Harris]

8 hours ago, Nickfromwales said:

Deffo go for the electric element in the towel rad over wet plumbing it. That way you don't have to have the entire pumped warm water system going for just a trickle of heat to the one rad. 

After that it sounds your ok, as it's far easier to use electric solutions here vs wet warm water systems as the cost and complexity soon becomes significant. 

Using very good room stats which won't have too big an overshoot ( good hysteresis ) will be vital. @JSHarris may be able to provide a link to his which, iirc, switch at 0.1oC increments. 

 

I fitted the widest towel rail I could find (1400mm wide, IIRC) that was also very short, top to bottom, so it can take towels side by side and won't overheat the bathroom too much.  I also fitted the smallest element I could find, around 150W, and have it wired to a time switch outside the bathroom, so it only comes on for an hour or so morning and evening.

 

The thermostats I used with the 0.1 degree hysteresis are these: https://thermostats4u.co.uk/products/computherm-q3rf

Edited May 7, 2017 by JSHarris

[CC45]

So the general thoughts are:

 

1. Towel rad with electrical element fitted for summer towel drying.  I think this should also be plumbed to the wet system for the rest of the heating period. Nick seems to suggest to not connect to the wet system - so elec used every day to dry towels - is that right Nick? Its not long or tricky to get pipework to it. @jack - I'd rather just spend the extra few £ and finish the job, I hate going back to a job.

 

2. Electric UFH

 

3. @Triassic as above - think I'd rather put them in I think.  Regardless of the temp the missus will express an opinion about temp (the switch on the heating control is the most used switch in the house - she puts it on and then I turn it off - several times a day, even now and its summer) + my father has kidney probs and does feel the cold.

 

4. Thanks @JSHarris for that link, clocked this a few years ago whilst reading your blog. Will check them out.

 

Off to the plot now, never ending.  Thanks chaps for your observations

 

CC

[Nickfromwales]

Yes, I'd not bother with wet plumbing the towel rad. It'll never be economical to run it off the wet system, and it'll be used so little, and mostly when the house is above ambient. That'll mean to get it to heat the towel rad ( essentially to overheat the room ) it'll bring the entire wet system into play, so the heater ( boiler / HP / other ), manifolds etc, and all the interconnected pipework through the house will be heated just to warm a towel . 

 

[Redoctober]

50 minutes ago, Nickfromwales said:

Yes, I'd not bother with wet plumbing the towel rad. It'll never be economical to run it off the wet system, and it'll be used so little, and mostly when the house is above ambient. . 

 

Sorry @Nickfromwales for what may sound a silly question but if the towel rad was linked to the wet system, servicing the UFH in the bathroom  / ensuite, would that not be a beneficial use of energy, in order to dry the towels as opposed to switching on an additional source of energy, namely electricity?

Or is it a case that if the towel rad was linked to the UFH, it would never reach a sufficient temp to actually dry them?

PW.

[Onoff]

That's what I'm doing isn't it, linking the st/st towel rad to the UFH manifold.

[joe90]

I am having electric towel rads in the bathrooms on timers as it's so much easier than wet plumbing and cost pennies to run for the short time they are required.

[Redoctober]

Thanks @joe90 - re-assuring to know the running costs are minimal but do you have UFH fitted ?

[Stones]

The 'problem' with using low flow temps in a towel radiator is that they will not provide any meaningful heat or towel drying over and above what you will get if you just hung the towel over a door to dry.

 

 Towel radiators / rails are designed to work with high flow temps ( all you need to do is compare the Btu output vs a standard radiator of the same size to see how much less effective they are at heating).

 

We had a wet towel rail plumbed into a low flow temp system in our last house, the bathroom was always cooler than everywhere else in the house and it did nothing to dry towels. We ended up swapping it for a normal radiator...

[Onoff]

Pretty sure that @Nickfromwales looked at my situation and reckoned that the temperatures for towel trying were available.

[Stones]

Our system had flow temps of 33C at 0C ambient, lower when ambient was higher. 

[Nickfromwales]

In a passive-esque house, you'll introduce a lot of nuisance heat trying to get the system to deliver heat that's actually useful enough to dry towels, considering the house will most likely be sitting at a comfortable ambient temp anyway you'll actually have to 'force' the system to deliver the higher grade heat. That heat will be set at the heater, and have to traverse all the piped system, so will likely waste more energy than save. 

If your an exporter of electricity then it's acceptable 'collateral damage' to run the towel warmer and UTH from grid electricity for the little time and consumption they'll require. 

@Onoff's situation is different as he won't have PH specs to save him from having to employ a higher flow temp, plus no MVHR, triple glazing, airtightness etc so not apples for apples there . 

Each situation is unique . 

[Redoctober]

Thanks @Nickfromwales for the clarification -

PW

 

Edited May 7, 2017 by Redoctober
Wrong info entered.

[joe90]

3 hours ago, Redoctober said:

Thanks @joe90 - re-assuring to know the running costs are minimal but do you have UFH fitted ?

Yes but only downstairs, if I did have wet radiators in the bathrooms I would tee them off the DHW cct which is near the bathrooms but decided on simplicity I.e. Electric radiators ( and electric UFH in the bathrooms).

[readiescards]

On 07/05/2017 at 08:57, JSHarris said:

The thermostats I used with the 0.1 degree hysteresis are these: https://thermostats4u.co.uk/products/computherm-q3rf

 

Looks like thermostats 4 u has closed.  @JSHarris could you kindly provide the model/manufacturer please?

[Jeremy Harris]

It's listed on Amazon, here: https://www.amazon.co.uk/COMPUTHERM-Q3RF-Wireless-Room-Thermostat/dp/B00SI2XDSI