Effectiveness/efficiency of radiant vs. finned baseboard

M.P.

Our 1960's house has hot water finned baseboard units throughout the first and second floors. The boiler driving the system is very old, and we're planning to replace it. While we're at it, though, we're wondering whether we ought to get rid of the baseboards on the first floor (the second floor doesn't bother us so much) and replace them with a staple-up radiant system. We called a local pro, and he told me it would cost about $8,000 to put a staple-up system in for half the first floor; presumably it would be about double for the whole space (about 1100 sq ft).
I'm trying to figure out if it's worth it. We haven't lived in the house through the winter yet, but everyone told us baseboards work great. Will a properly designed radiant system be as effective? Will it be more or less costly to run?
And finally, is it really worth this much money?

hr

radiant rules!

in areas where you stand a lot or are naked and wet. Bathrooms and kitchens, greatrooms, etc.

For me radiant floors are a bit of an overkill in bedrooms, especially carpeted ones Panel radiators or baseboard make more sense in rooms that are used for sleeping.

It's fairly easy to retrofit radiant and combine it with the baseboard system. A simple mix valve to supply lower temperature to the radiant zones. Or consider the UltraFin product.


hot rod

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M.P.

One of Ultra-Fin's claimed selling points is that it's compatible with hardwood floors. Are other staple-up systems (with the aluminum panels) more likely to harm our wood floors? I've read the big "panels vs. no panels" document on this site, and I didn't see anyone arguing that systems that only heat the air between the joists are safer for hardwood floors. Is Ultra-Fin just engaging in marketing, or should this be a real concern for me?

GMcD

Envelope

Not much is going to change the total energy use of the house: heat lost = heat that needs to be made up, no matter what the heating terminal type is. If the heat losses are high, then a radiant floor system, especially inefficient staple-up, will have to be run at high temperatures which may have to be high enough that they will cause hardwood floor damage.

It's my advice that the first step is to spend some money to minimize the heat losses of the house to get direct energy savings and allow you to use a smaller replacement boiler and properly design a combined radiant floor/baseboard/panel heating system.

So that's the heating system discussion- what's the ventilation system in the house? If envelope improvements are made, you will need to have "some" mechanical ventilation with a heat recovery ventilator for a healthy home.

Is it "worth it"? I can't tell you about your own comfort and health - that's your call. What's your comfort and health worth?

ALH_4

It depends

With a properly controlled system, particularly with outdoor reset controls, you have little to worry about with aluminum plates. I'm not sold on Ultra-Fin yet.

Steel panel radiators sized for reduced temperatures are a nice, cost saving, way to go if you're thinking of installing a condensing boiler at some point in the future.
I agree with hot rod about radiant being more appropriate in certain rooms or certain circumstances. You can always have radiant in your bathrooms and kitchen and have panel radiators everywhere else and keep your costs down.

-Andrew

M.P.

What's a heat recovery ventilator?

Thanks for the reminder about the importance of minimizing heat loss. We've got some fairly large windows on the first floor, so we may conclude that radiant under hardwood is not a good idea if, as you say, any radiant system would have to be run pretty hot to keep up with the heat loss.

I'm a novice (obviously), and so I don't know what a "heat recovery ventilator" is. Can you educate me?

Ron Schroeder

don't forget that

You can design your infloor radiate for a design temp and then add extra heat on cold days via two stage t-stat and use radiate panels or baseboaerd to cover the rest.

hr

Any system that overheats the wood

can cause harm. Most hardwood manufactures will indicate the temperature limits for their products. Of course meeting the load with the lowest possible supply temperature would be ideal. And yes, there are times when radiant floors are not the correct or best choice.

I'd put UltraFin between transfer plate installs, and the direct tube staple ups as far as transfer from the tube to the floor. Keep in mind one of the largest radiant manufactures has been selling suspended pex systems for years with good sucesss. Again IF the loads are in line with the pratical output of that installation method.

To my way of thinking UF is a suspended tube "amplifier. Just as transfer plates are to direct tube staple up. I doubt that any part of the wood flooring approches the temperature that the tube is supplying. The "air" conductor (convection transfer)just isn't powerful enough.

Wood floors can be abused regardless of the installation method. More often than not poor temperature control logic, or a load that is beyond the radiant panel's reach is the real issue.

Each system has it's pros and cons. Just like boiler selection as our friend Perry is learning

Here is some UltraFin and transfer plate at work under the eye of the infared camera. Pretty nice temperature spread with the UF, but higher output with the ThermoFins.

Notice the cold air near the entry door, and the white hot carpenters compressor

hot rod

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GMcD

HRV

It's a small fan/ventilator unit that exhausts stale humid air from the house, with the warm exhaust air passing through an air to air heat exchanger section to pre-heat the incoming fresh air being supplied into the house. Depending on how much ventilation air you need for bathroom exhaust, dryer make-up, range hood make-up, you can also add heating and cooling coils to the supply air stream for supplemntal heating and cooling.

Google "Venmar" or "Lifebreath" for a start, and there are other brands out there. Pretty well all building codes for new houses require a minimum air change rate in the home of between 0.35 and 0.5 ACH (Air Changes per Hour)