Low Temp Radiant Panels to supplement heat pump in NH

LuckyDog

Attached is my master bedroom idea / plan.
The red boxes are were I plan to locate the radiators.

Location: Freedom, NH
Design Day Temp: -9°F (Manual J)
Heat loss: 10kBtu/Hr (at -9)

I have a Mitsubishi mini-split AC/Heat unit for summer and knee seasons - but I figure by 10°F it is insufficient and not worth anything by -9.
So, I am looking for panels to cover the 10k required.

Downstairs and basement are all radiant floor heat. Lightweight gypcrete over-pour. The water temp on design day is 126°F.

I think a pair of these Beacon Morris BM-22-24X56 radiators and a BM-22-24X36 covers my needs.

I will be using ODR. The plan is to let the upstairs run whatever the ODR says is correct temp for the main floor. There will be a thermostat upstairs, but an in-floor temp sensor control for downstairs and basement. Three zones total.

Does the placement of the radiators look ok?
The wife and I like the bedroom cooler. So we don't care if it cannot maintain design temp on the coldest nights. I just don't want any water freezing.

hot_rod

Placement looks fine, under windows is another typical area to install emitters. looks like you don't have a lot of wall space options?

LuckyDog

Thanks Hot_Rod.
That was the best I could think of. The windows either side of the French doors are full length. The wall at the stairs is only 3 ft. high.
My only other thought is Runtal Vertical radiators, but I would still need three radiators; and Runtal is a little pricey.

One more question....
I have about 270 feet of 1/2" PEX left from the radian floor installs.
Which do you recommend I do?
Home run each radiator?
Plumb the radiators in a loop?

//Paul

hot_rod

be nice to have them controlled by TRVs, so a home run piping

obviously a circulator will need to be enabled as well as the boiler, somehow

LuckyDog

Would TRVs be instead of, or in addition too, a wall thermostat?
I get how TRVs can even out the heat in a house that is only using one thermostat. I was looking at this as sort of a one-room thing.

hot_rod

TRV could give you individual control at each rad

A central wall stat may be used in conjunction, depending on piping

Some control needs to fire the boiler and circulator

Delta P circulator with an induction relay could trigger a heat call