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How to heat a standalone office / bathroom

onobed Member Posts: 1
edited June 2021 in THE MAIN WALL
I am building a standalone office with a bathroom. The bathroom is 85 squarefeet.
I live in Santa Cruz California. I plan to use electric radiant with a toekick heater for those times I need extra heat.

I have read that hydronic is better - but for such a small space, I don't feel the extra space and complexity of hyrdronic is unwarranted.

The rest of the office will be heated by a minisplit.

I do have hydronic in the main house - but I feel I will lose a lot of heat running the hot water the 15 feet to the office.


Thanks in advance.


  • mattmia2
    mattmia2 Member Posts: 5,531
    Running hydronic piping 15' will lose little if you insulate it. A mini split would be a great way to heat and cool. As always heat loss and heat gain calculations are the first step.
  • Jamie Hall
    Jamie Hall Member Posts: 18,947
    Santa Cruz? The minisplit will be ample for the office, and do you even really need additional heat for the bathroom?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 5,531
    There are mini splits that can use ductwork for distribution, maybe use that type to serve both rooms. AC likely is more of an issue than heat.
    EBEBRATT-Ed Member Posts: 12,007
    California just put some electric baseboards or an electric wall cabinet heater.
  • Intplm.
    Intplm. Member Posts: 1,376
    Look into a correctly sized Mini-Split system. You should be very happy with that considering your building size.
  • Dave H_2
    Dave H_2 Member Posts: 503
    I think the bigger question to ask is do you plan on AC in this space?

    If not, cost wise, I would go hydronic. its already there, a little pipe and element, a zone valve and a little wiring, not too shabby!

    If you are using a mini-split for the AC, well then that's a done deal cost-wise...
    Dave H
  • Lance
    Lance Member Posts: 209
    Dear Dave, I have done many of these before. For such a small space I recommend electric radiant for three reasons. 1) Independent zone and control 2) low expense installation. 3) Low cost in operation as usually a new space has superior insulation and a low heat load. 4) All my customers who did this were very happy with the results. Even if you choose a Heat pump for the office space, electric for the bath area is best where we size for 115% of the load. After all, this is a clothing optional room. and can also have its own control.
  • ethicalpaul
    ethicalpaul Member Posts: 3,739
    Mini split without hesitation. I'd never install resistive electric anywhere, but especially not in sunny California.
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • hot_rod
    hot_rod Member Posts: 16,315
    how large is the office portion? If you want cooling and some dehumidification, a mini split may be the best option and small sizes are available. Heat only for that size bath I would look at electric radiant from an install and cost of operation. Depending on boiler type and size, possibly run a hydronic loop.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 3,201
    I have read that hydronic is better - but for such a small space, I don't feel the extra space and complexity of hyrdronic is unwarranted.

    Double negative is unclear. is this what you meant to say?

    I have read that hydronic is better - but for such a small space, I do feel the extra space and complexity of hyrdronic is warranted.

    and 15 feet is nothing! Unless you forgot to place a zero at the end... 150 ft is still just fine. that is what they make pipe insulation for.
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org
  • bill_brooks
    bill_brooks Member Posts: 49
    when i built my house, hydronic radiant was a must. but...... even in the summer there are days when the
    bathrooms needed a bit of heat. for this reason, i chose electric radiant. not only for cost upfront, but to
    eliminate the need to fire my boiler for such small heat loads (60,75sqft.) i suppose i could have gone the
    wall heater route, but i didn't want to listen to the fan noise. the floor-sensing stats were a bit pricey but
    worth it.
    the turn-down of my boiler, plus it firing a 40gal. buffer tank would not cause short-cycling. but there it is. i'm happy with my design.
    BTW: firing the boiler into a buffer tank (rather than the heating zones) may seem unconventional. but
    in high demand cycles it keeps the on/off cycling to much longer periods. a positive scenario.