Upper floor under floor heating vs. rads

[JamesN]

I'm looking into the best way to heat the upstairs of my new-build, 2-storey house with heat pump. I'm interested in the pros and cons of radiators versus underfloor heating and would also appreciate any insights into the cost difference between the two. For context the the upper floors are wooden joists.

I'm considering the impact of low water temperatures and flow rates on radiator sizing for my new build. I've heard that larger radiators might be necessary in this situation. However, since the house is well-insulated, with triple glazing, this would reduce the required radiator size. Do you think it's possible to achieve efficient heating with smaller radiators on the upper floor, especially if they're on a separate zone?

 

If you've had any experience with this, I'd love to hear your thoughts!

Edited December 4, 2024 by JamesN

[ProDave]

Build the new house properly insulated and air tight and you won't need heating upstairs.

[nod]

1 hour ago, ProDave said:

Build the new house properly insulated and air tight and you won't need heating upstairs.

Plus 1 

[JohnMo]

1 hour ago, ProDave said:

Build the new house properly insulated and air tight and you won't need heating upstairs.

Unless you go and take the grant - then it's mandatory.

 

1 hour ago, JamesN said:

I'm interested in the pros and cons of radiators versus underfloor heating and would also appreciate any insights into the cost difference between the two.

Pro UFH, can have low flow temps with very little thought about design. Materials wise can be cheap to install. but you could pay an arm and leg to install.

Neg UFH, very slow to heat up and cool down once up to temp. So if you have an elevated temp before going to bed you will likely have that temp for sleeping - like it or not.

 

Pro rads, can be cheaper to install, they are more reactive than UFH

Neg rads - use wall space.

 

If going for a grant

Have a design flow temp of 50+ (most big companies want you do that), design temp in bedrooms as low as allowed, that will allow small radiators in bedrooms.  Then switch them off once commissioned and follow what @ProDave says. Then run the system as a single zone.  Make sure the install does not include a buffer and the heat pump isn't massively oversized.

[JamesN]

Hi All thank you for your responses, I really appreciate it guys.  To update the post - the house is actually 3 stories with a study and bedroom on the top floor. Does this change anything above?

[JohnMo]

1 hour ago, JamesN said:

Hi All thank you for your responses, I really appreciate it guys.  To update the post - the house is actually 3 stories with a study and bedroom on the top floor. Does this change anything above?

Not really - bigger question is are looking for a grant for the ASHP?

[Glenn]

Mandatory upstairs heating a really interesting one. For my (admittedly very small) house but well insulated and airtight house I had estimate/quotes from 3 suppliers. One did mention they wouldn't proceed without installing heat upstairs, the one I went with (and who processed the grant) was happy to go with heat calcs based on ground floor UFH only. 

Edited December 4, 2024 by Glenn
typo

[JohnMo]

34 minutes ago, Glenn said:

Mandatory upstairs heating a really interesting one.

So premise for the statement. To get BUS grant, need to design and install to MCS rules. MCS rules require room by room heat loss assessment and be able to maintain a minimum design temperatures, at outdoor design temp. You can easily borrow heat from downstairs, but only really true if you leave the bedroom doors open. There is also an understanding written into MCS, that the rules for design are not really applicable to what 'you want', as the person having the insulation, but also suitable for the next buyer(s) of the property. It's everyone's money being utilised to pay for the £7500 max grant.

[JamesN]

Hi,

 

We're planning to apply for the ASHP grant as we're eligible due to being a self-build project.  I can't foresee any reason why we wouldn't, unless you can think of any reason?

 

So it seems according the MCS we'll need to get an accredited assessor to assess each room and plan for emitters (UHF or radiators) throughout the house in the livable rooms.

 

To move forward, is the best thing to send our plans to a heating specialist for quotes and system design?