Home>Discussions>INSULATION & HVAC>"adding" hw baseboard heating to in-law space
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"adding" hw baseboard heating to in-law space

Have a Cape heated by hw baseboard - the previous owners added on
an in-law bedroom & bath off back of house, and installed electric baseboard for this space.

We'd like to know if its reasonable to think one could simply "attach" new hw baseboard into the in-law space by way of the existing hw baseboard in the adjoining bedroom - and thus do away with the electric baseboard?

Have called a couple of HVAC people to give quotes, but it must be a small job (or an unpopular job), and none of been out. Then I wondered if this was something a licensed plumber would do since
it seems like its a matter of piping (unless I'm totally mistaken).

Re: "adding" hw baseboard heating to in-law space

Yes, it's a matter of piping, but other factors have to be considered:

1) does the existing boiler have enough extra heating output (called BTUs/hour) to heat the additional load of the in-law bedroom/bath & at the same time keep the rest of the house warm---the fact that electric baseboard was put in previously indicates that a) the installer of the EB took the easy way out since elec baseboard is easier to install; b) the installer did a heat study of the extra space & determined that the boiler output was too small to take on the in-law space---however, in almost all cases, the boiler has sufficient extra output to also heat such an addition---you're lucky to have HW heat; it is one of the most flexible systems available for such modifications---and yes, I think you will save lots of $$$ on the electric bill by having all the house heated by hot water--in essence, this would allow the modification to pay for itself within a short time; the elec baseboard could be left in place to serve as emergency heat if the boiler should go down.

2) will you be able to find a hydronic (hot water) installer/technician that is familiar with adding and extra "branch" or ZONE of piping, and perhaps a separate thermostat to the in-law section---the hot water piping/baseboard usually can't simply be "attached" to the existing HW piping in the house, as this may create too large a piping loop that will compromise the heating in another part of the house.

If you can post back with some numbers as to a) the total square footage of the house without the inlaw addition and b) the total square footage of the in-law bedroom/bath, and its total square footage of window glass; c) the average height of the ceilings; d) the total OUTPUT of the boiler in BTUs/hour---this boiler info is usually stamped on the front of the boiler and will say something like "OUTPUT: 60,000 BTUs/hour"; e) your general location in New England & your average lowest temperature experienced in the winter.

These figures will indicate if you have enough extra boiler output to heat the addition, & how many feet of baseboard you will need to heat the addition.

To find a hydronic (hot water heat) installer who is familiar with this type of work, consult the Yellow Pages under "Heating Contractors", many of them have a little display ad in this section that specifies the type of heating work they concentrate in; also consult the YP under "Fuel Oil" or "Oil Dealers"; nearly all oil companies have techs who do this sort of work & are also licensed to work on gas-fired equipment; also consult the YP under "Heating Equipment--Parts" to find heating parts houses in your area; go in & ask the COUNTERMAN to recommend several hydronic technicians that do these types of additions---also go to the Building Reg dept. of your local city hall & ask the see the building permits issued for a recent month--sift thru the ones that indicate hydronic heat work done & copy the name of the company/technician that did the job---you might even try calling the homeowner of each job listed to ask if they were satisfied with the work done by the contractor.

Get at least 3-4 estimates before you hire anyone, as there often is a considerable variance in the cost estimates for the job; when a reasonable tech is found, insist on a written contract as to what work will be done, that a heat loss calculation be done, the begin & finish dates stated, and the cost of the job stated.

Please post back.

Re: "adding" hw baseboard heating to in-law space

The main "house" is 1200 sf Cape, and the in-law space is 192 sf. The house has 3 heating zones - the main house, the basement rec room (which is 360 sf & heated by a wall unit), and a 336 sf family room (heated by hw baseboard).

Have a Buderus G124X/18 - installed in 2008.

Re: "adding" hw baseboard heating to in-law space

Some of the requested info is still missing & may have a bearing on the final heat loss calculations.

For example if your location is in the far north portions of New England, this is quite different heat-loss and temperature-wise from southern New England.

Likewise, the amount of glass (windows) would have a bearing; & although not mentioned before, the amount (or presence if any) of exterior wall and attic insulation is important, as well as ceiling heights, etc.

The heat output of the Buderus Logano G124X/18 is rated at 61.4k btu/hr IBR or 53k btu/hr DOE.

A heat loss calculation can't be done until the rest of the data is known.

However, 192 sq.ft. is not a large area (assuming normal glass & ceilings/location,etc.), and this is usually able to be heated by approx. 15'-20' of baseboard, installed as a separate zone---this would also provide a separate t-stat to turn down the heat in that section when it is not being used.

Despite the missing data, if you are now experiencing reasonably prompt response to turning up the thermostat in different parts of your house & getting heat within 10 minutes to 1/2 hour, I don't see you having problems with adding another zone for the in-law/bath addition.

Re: "adding" hw baseboard heating to in-law space

Located in northern CT. The in-law has only one window (the other side of this room "butts up" to a 3-season porch). The in-law bath has one room. The # of windows & their location is fairly typical for a 70s Cape. Ceiling height is 7 1/2'.

After much discussion, the Buderus is now "left at" the highest desired temp (as opposed to setting tstats back, and then turning'em up). While we haven't seen a significant savings compared to our 40 yr old boiler, we're probably spending the same amount to have the house consistently 5-8 degrees warmer. But its very hard to break the habit of you'll save on energy costs by turning your tstats down during day, and then turning them back up once everyone gets home from school and work.

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