8 posts / 0 new
Last post
Bathroom heaters

I live in the Chicago area. I am renovating a 100 year old bathroom (have contractor doing the work). The area is 64 square feet. It had no insulation but now will be completely insulated and will have a double thermal pane window. I will have a small 4 foot baseboard hot water radiator in the room; but, I usually do not leave the furnace on to heat the entire house at night. In the past the bathroom was very cold in the morning. I am hoping that the insulation will do a lot to keep the area warmer on a cold morning, but I am looking for a heater specifically for the room. I can continue to use my tower infra red space heater but it will ruin the look of the new renovation. Any suggestions for another solution? I can tuck a small parabolic behind the toilet (may not be safe), use an overhead heat lamp (not too pretty), install an in-wall coil (not fond of blowing air), etc. I am afraid to spend on something that will not solve my problem. I want the room to look like a 100 year old bathroom, but nicer quality than what was there before. I think the fixtures and tile I have chosen will do this, but, what about heat? Any suggestions?

Re: Bathroom heaters

An 8' X 8' bathroom (64 sq.ft) is a rather small bathroom (I assume you have an 8' ceiling, if not please advise)---nevertheless, even a small bathroom is often hard to heat comfortably , since it requires keeping occupants comfortable when coming out of a shower, especially on a cold Chicago winter's day!----the sizing of the present 4' of HW baseboard simply wasn't a good idea, whoever put it in a number of years ago----HW baseboard heat output is calculated in BTU/hr heat output per linear foot at the boiler/piping system HW temperature, typically 160 degrees/400 BTU per hour per lin.ft. = 1600 BTU/hr for 4' of hydronic (hot water) baseboard----only HALF of what you need to adequately heat that room---the BTU (British Thermal Unit) is the unit of heat that is used by heating contractors to estimate & calculate how much heat appliances/baseboard, radiators, heaters, etc. put out while heating a room or building, and correspondingly how much heat is required to heat a particular room based on its size, sq. footage, amount of insulation inside the walls/ceiling, etc.----any heat produced by a heater in the bathroom will gradually (sometimes rapidly) escape right thru the floor, ceiling, exterior walls (depending on how much, if any insulation they have), thru glass windows, open doors, etc.; this is a BTU/hr heat loss, which has to be replaced by added heat from a heating appliance rated at a certain heating output, BTU/hr heating output; extensive bathroom wall/floor/ceiling insulation & double pane windows will greatly retard this heat loss.

Your first step should be to touch the supply piping to the bathroom baseboard to see if it's cold (as it probably is), then turn up the house T-stat to get heat & see how long it takes to feel high heat with your fingers on the bathroom supply piping, if the piping gets so hot you can't keep your fingers on there, you're lucky---you have a good supply of heat/hot water going into the bathroom baseboard & you may be able to solve your problem by expanding the amount of baseboard/radiator footage (below); if your fingers tell you that the bathroom supply piping doesn't ever get really hot, or takes quite a while to do so, you may have to consider the other options below to solve your cold bathroom problem.

The amount of heat needed for a 64 sq.ft. bathroom to keep it comfortable on a cold day is calculated at 50 BTU/hr per each sq.ft X 64 sq.ft.= 3200 BTU/hr to keep the bathroom warm & comfortable-----4' of baseboard, even when producing its full heat output can only put out 1600 BTU/hr of heat---and this isn't taking into account the rather slow response of HW heating, especially if the bathroom baseboard piping takeoff is "at the end of the line" in the circulating piping heating loop coming out from the boiler, so if the T-stat for the system is located in the living room & it is turned up, it will take quite a while to get heat into the bathroom.

Thus, the sensible thing to do is to have SPECIFIC CONTROL over the heat needed in the bathroom---a room that requires TWICE the amount of heat per BTU/hr per sq.ft. than any other room in the house---this is done by having the bathroom have its own T-stat, that can turn on the boiler by itself, or turn on an electric heater by itself to heat only the bathroom----the bathroom zone.

There are several ways to do this:

1) modify the HW piping system so that the bathroom is on a SEPARATE ZONE with its OWN THERMOSTAT---this is done by installing a ZONE VALVE near the boiler & installing separate piping with a T-stat in the bathroom---this will turn on the boiler according to what the T-stat is set at in the bathroom (usually a little higher than the rest of the house)---the new separate piping from boiler to bathroom will then pump HW directly to the bathroom thru the new zone valve until the bathroom t-stat is satisfied; it also gives the occupant the option of raising the temp in the bathroom in the AM when most people take a shower & want a warm bathroom when they come out soaking wet from the shower----pricing for this option would be approx $60 for the ZV, $100 for piping & T-stat, added baseboard footage, or better, a hydronic (hot water) kickspace heater ($100) at the base of the sink vanity or built into the base of the bathroom wall & approx $200-$400 for installation/labor---get some estimates, I'm just guessing here; the advantage to this option is that the boiler comes on for a short time only to heat the bathroom, and doesn't waste additional fuel in heating the rest of the house.

2) Forget about modifying the HW system & have an electric kickspace heater installed at the base of the sink vanity w/T-stat @ 3200 BTU/hr & push-button timer; typical unit is 1500 watt @ 5,000 BTU/hr; separate fuse & dedicated elec line to the main elec panel approx $300-$500.

3) Forced hot air elec wall heater w/fan & t-stat that fits inside base of bathroom wall 16" stud opening @ 3400 BTU/hr @ approx $170.

4) A number of homeowners these days are installing bathroom radiant floor heat (either electric or hydronic (hot water)) where the entire sq. footage of the bathroom flooring is thermostatically-control heated by buried sub-floor flexible plastic PEX heating tubes or heating cables----this option is considerably more costly than the above options.

5) Since you don't like air-blown heaters, another option is to stack several 4' sections of HW baseboard all piped together over the one you have in there now---this will save space & give you 12- to 16' of HW baseboard in a very small space, to produce 4800 to 6400 btu/hr---but you would still have to have a zone valve/T-stat installed to make this a separate zone; there are also new stainless steel wall-hung radiators designed for bathrooms, or perhaps even a used/rebuilt 4' cast iron radiator rated at approx 6400 btu/hr, if you have enough room----cast iron & stainless rads put out a lot of heat, but again would probably have to be put on a separate zone.

6) Another idea would be to install an overhead combo of a bathroom light/exhaust fan/radiant heat element all in one unit that is controlled by a push-button wall timer set for 5, 10, 20 or 30 minutes. http://www.google.com/search?q=bathroom+combo+fan/light/heater&hl=en&noj=1&source=univ&tbm=shop&tbo=u&sa=X&ei=qhpkUqKtCsOayQGr84CYDw&ved=OCEEQsxg&biw=1024&bih=717&dpr=1 This could very well be the best way to go---especially if you already have an overhead exhaust fan installed (as every bathroom should to expel bathroom moisture)--the install could probably be done for approx $200-$300 & you're good to go!

Kickspace heaters (both elec & forced hot water) are widely used in bathrooms, because they take up a very small amount of space (12" X 4"), are recessed into the wall, & are thus ideal for small square footage bathroom spacing, and they put out the 3200 BTU/hr that's needed to quickly heat up the bathroom without waiting forever for the hot water system to provide heat into the bathroom, when it's needed RIGHT AWAY-----some kickspace heaters can be noisy when running, so get one that's quiet.

The upfront installation cost of the hydronic/hot water zone valve option would be considerably more than putting in an overhead fan/lite/exhaust/heat combo, or an in-wall t-stat controlled elec fan heater, but over the long run you might spend less on fuel costs for a natural gas/oil boiler-fired system that often costs less than electric in the long run.

Your best bet is to get some estimates from hydronic (hot water) heating contractors (Yellow Pages, 'Heating Contractors"), or electricians, if you opt to have an elec system installed (Yellow Pages, "Electric Contractors").

Re: Bathroom heaters

An electric towel warmer can add some supplemental heat to the bathroom. They look good too. If that is not enough, electric radiant floor heaters can do the job as well, and you can put them on a timer so they only come on when you need them.

Re: Bathroom heaters

Electric floor heat would be my vote.

Re: Bathroom heaters

Floor heat in a bathroom is awesome- if you can easily access the underside of the floor. If not, go for the vanity toe-kick heater. It will be hidden and effective and probably the easiest permanent install so long as you can get the needed power (and piping if you use the existing plant) run to it.

Warning: Once you experience floor heat in a bathroom (especially with a tile floor) you'll be hooked forever!


Re: Bathroom heaters

Home Depot carries an oil-based radiant heater that looks like a small radiator for about $45.

Re: Bathroom heaters

I have a 10 foot square bath with 15 foot ceilings. Although the hot air vent puts out good heat, it all goes up to the ceiling. The house is well insulated, but I was always feeling cold when showering in the winter. The solution was a 2000 watt surface mounted heater from the german company Siebel It uts out over 6000 btu's and has a cage blower which rapidly throws the heat all over the bathroom. The unit cost about $120. An electrician ran a 220 volt line all the way bake to the service box for less than $200. 2000 watts is a fair amount of electricity to use, but it is only used for a few minutes per day. To me, it makes more sense to be able to rapidly raise the temperature in the bath rather than install a source of heat that either keeps the room too warm all day long, or is too slow in bringing up the heat.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.