Hello All,
Wondering if anyone has any insight/experiences with removing an old HVAC unit from the roof of an eichler and going back to radiant heating. I realize this isn't going to be a cheap procedure, but looking for some practical advice. Any input is greatly appreciated.
Thank you!
Hey, let's try to keep it clean here. :wink:
thanks for the heads up...fixed ;)
Most Important - you need to capitalize EICHLER (minor nit-picking? yes)
Then, you must see if your radiant heating works properly. I love radiant heating. It works with doors closed. Try closing a door with forced air and you can have your system straining to achieve nothing.
A/C contractors hate to hear this, but.....Eichler owners with foam roofs seldom consider getting air conditioning. Here's why. When you put the insulation on the very outside of the building envelope, there is NO heat gain soaking into the Eichler from the outside. Sunlight puts out 1000 watts per square meter of roof, noon-time, summer-time. What if only 25% of this gets into your Eichler. Picture your ceiling covered with glaring light bulbs. With old-style roofing, you soak up this heat, and then try to insulate and keep it out of the house. This simply cannot work. It is a much better idea to prevent the heat gain in the first place. This can only be achieved with the insulation on the very surface of the structure.
thanks randy from durafoam roofing. Are you a grammar nazi or a roofer?
...Wait, sorry, I forgot to capitalize and hyphenate... one day i'll learn.
my bad
Oh...and thanks for the completely off-topic response...
Agree with Randy about the foam roof. Since we got one our house in Orange has been cool as a cave (almost). The back wall faces south into a large pine and the smaller east and west facing windows have duplex honeycomb blinds. The carpet has been replaced with tile so that the slab acts as a heat sink. An induction cooktop and lots of compact fluorescents complete the picture. We open the house up at night to fill it full of cool air and close it up in the morning and by the end of the day earlier this week during a heat wave the temperature was in the high 70s indoors with a high in the low 90s outdoors. Only the fourth bedroom (the one that opens onto the atrium) gets any solar gain and heats up during the day because my husband won't let me put blinds in there. It is a classic passive solar heating/cooling set up, albeit with "too much" glazing.
We have a couple of folks in our neighborhood that completely took off entire roofs that were inappropriate so I doubt it's that difficult to take off AC ductwork (if that's what you're talking about). The challenge will be repairing the roof. You'll probably have to reroof. (Randy is correct about foam-except for the two weeks of the year it's over 100 degrees.)
You'll then have to figure out how to repair the holes in your ceiling. Much more difficult.
If your radiant can be hooked back up great. Then it's time to get a boiler for $3-5k. Plus the cost of checking for leaks before you make the investment. And then pray that the system doesn't fail.
If your radiant system doesn't work you can go with a low voltage electrical system under tile (questionable) or do a real radiant system by pouring a new inch and a half slab on top of the existing one. This will then require all doors, windows and cabinets be adjusted to the new floor height. Quite a number of high end renovations seem to go this route. It seems to require a gut job to do right though.
It may just be easier to go with a high velocity unico system under a new foam room. It's not an eye sore and you end up with a high performing system for the life of your house for $30-40k.
Hi Moesch,
Sorry to be late to the party...
I didn't see you mention where you are located. Indicating location is important for several reasons: climate assumptions, contractor recommendations, neighbors who might be willing to show you there setups. Since there's a 90% or so chance you're in N. California, I'll make that assumption unless you indicate otherwise.
Here is what I would want to know to make a decision you're facing:
- what kind of radiant pipes do I have? If they are steel, I'd forego trying to fix them (they rust out). If they are copper, I'd seriously consider getting them inspected for viability. I've heard they can do this without a boiler attached.
If the radiant is worth resurrecting:
- you will need to cost out repairing any leaks and installing a new boiler (I'm assuming the old one doesn't work).
- you will need to consider the cost of removing/replacing any floor coverings that would impede heat flow (carpets, etc.)
- you will need to cost out removal of the HVAC and repair of the vents.
If the existing radiant is not worth resurrecting, you can still have radiant heating as Tom mentioned.
- For myself, I'd stay clear of the 'warmfloor' heating as I hear the bills are very high. Of course, talk to some people who have it to be sure.
- I also wouldn't want the pain of raising cabinets, doors, etc. required by pouring a new floor.
- A novel approach I've heard from a contractor familiar with Eichlers is to cut new channels in the existing slab and laying the modern radiant heating flexible lines. I'd probably investigate that further--especially if it was a newly purchased home and I expected to be reflooring anyhow.
The final option if your radiant can't be resurrected is to go the unico-like route which does allow both heating and cooling. However, you're definitely going to want to invest in carpets/carpeting as you are not going to feel warm with a ice cold slab beneath your feet. And you will have to decide where you want the 2'x3' or so unit installed inside for each zone.
Let us know what you find out. Tom and I have new neighbors purchasing a home in our tract with exactly your problem.
Cheers.
Jake
Thanks for the info, Jake and Tom. There was an Eichler for sale in Fairglen not too long ago that had HVAC on the roof. I was interested in putting an offer on the home but curious about costs to "fix" the roofline and redo the radiant heat. Moving forward, I now have a good idea about the cost/labor to restore roof/heating back to original specs. Appreciate the insight.
Moesch
Removing ductwork is easy. It's light and can be separated without much effort whether you unscrew it or cut it up. A crane to put the old HVAC (heating ventilation air conditioning) unit on the ground can cost $400. There are inexpensive junk hauling companies around that could throw the ducts into a truck from the roof, and then throw (?) the old HVAC unit on top of the ducts...to lessen the impact. If the unit still works, you may be able to sell it.
Now all that's left is the short, metal duct pieces that go through the roof. Roof boards had holes cut in them when these air outlets were installed. You cut out enough roof for access, then replace the affected boards.
Or...instead, don't disturb your roof. Leave the outlets, and larger air-return in place. Neatly cap the ducts and other openings. A metal shop can make anything custom you may need. Someone may want A/C in the future, and much of the work will already be done. They could install the flat same 4" tall, flat rectangular ducts we use with a Unico system above the roof insteak of hiding it inside the roof.
Well its 93* today in Walnut Creek and working from the House would be Impossible if I didn't have my AC on.
Have a great 5 year old Foam roof that works wonderfully but
the cool air is a must. Especially in the front of the house where I work.
@randy - thanks...this info, too, is helpful.