Best Method to Heat Old House
Hello All,
I need some advice on the best way to heat the house pictured above. Right now it does not have any central heat-just a couple of direct-vent gas heaters in a couple of rooms. The house is located in Alameda CA in a relatively mild climate that does not really require AC.
Lets assume that I will retro fit decent insulation into the walls-ceilings (sprayfoam and densepack cellulose) and seal up all the holes in the building envelope. I will not be removing the still in fine shape original wood double hung windows-but I will be weather stripping them somehow.
There is room on the bottom floor for a furnace. Because of the, beam below the joists, construction running heating ducts to all areas of the middle floor will not be a problem. We took out the chimney and the void left behind is plenty big to run heating ducts to the top floor. The bottom floor is slab ~2′ below grade construction with a shop-garage (which does not really need to be heated), a bedroom, a laundry room and a bathroom. Each floor is about 1000 sq ft.
I have read a lot on here about radiant heating but in this retro fit situation I don’t know that it makes sense. I think I would have to do the staple the tubing to the underside of the joists method on the top two floors and that does not seem ideal to me.
So my main questions are, forced air or retro-fit radiant? High eff nat gas vs gshp? What type of professional would I engage to get this system designed intelligently?
Thanks,
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Edited 8/8/2007 5:24 pm by madmadscientist
Replies
Nice shack!
Sounds like the forced air will work, but if you can use radiant, go for it. Especially if you intend to live in this house. Residential heating just doesn't get any better than radiant. It's also quieter and takes up a lot less space -- smaller heating unit, not registers that you shouldn't block, etc. That would mean pretty much gutting the ceilings on the first floor, but it sounds like you're OK with that. And, I'd rather run PEX than duct any day. I hate running duct.
I learned something yesterday from a poster here who does radiant. I had been using quick-trak to install radiant above the subfloor thinking, like you, that the between the joist isn't very efficient. He pointed out that using the proper fin product between the joists can actually be more efficient than the quick-trak. Check out his post here: http://forums.taunton.com/tp-breaktime/messages?msg=93208.9
Mike Hennessy
Pittsburgh, PA
I guess my question is, will radiant actually work in a retrofit situation? Thru the subfloor and thru carpet and pad? The top floor of the house is going to carpeted-will radiant work thru all that material?
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Should work fine. Once you stip the ceilings, you are as good as new install.
Mike HennessyPittsburgh, PA
it does depend on the carpet. if it's original carpet... perhaps not. You can always choose a carpet good for radiant, if it's to be new. sponge rubber pads are best, and thin synthetic fibers for the carpet itself.the thickness of your existing subfloor might work against you though: some old houses I work in have 2 or 3" of wood in the "subfloor"?-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
the subfloors here are full 1" 1by6 doug fir boards. You bring up a good point about the carpet...the wife is only going to want a nice thick cushy carpet in the master bedroom retreat. That'll make the radiant not work?
So, really the staple up to the underside of the subfloor is going to work well?
I have to admit I am having a hard time getting my head around the heating with radiant thing. Never touching your thermostat?? Takes a couple of hours to heat the room up?? Man that's strange.
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
that time delay thing is primarily for non-plate joist systems (very poor conduction), mass systems like concrete which take awhile to heat up, or perhaps a system with outdoor reset where the water temperature is set to just barely what is needed at any time... which is better than being able to set back water temperatures, usually . A plated joist system can heat up pretty quickly though if the water temperature is higher or responsive to indoor temperature conditions.Thick carpets can make radiant ineffective. High heat loads can too.The sponge rubber pads are pretty comfy.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Radiant has been used with great success in the walls and ceilings, too, not just for floors.You might consider a radiant ceiling in the MB and the shower walls in the bathroom.SamT
How about the tried and true hot water baseboard type of radiant heat? You could use the same kind of gas fired boiler, no chimney required, just a simple exhaust pipe out the side wall. It's easier and cheaper to install, can be zoned easily too.
Before radiant floor became available, hot water baseboard was always the radiant system of choice. It's silent, responds quickly to the need for heat, heats the room from just above floor level. For a house like yours, it may be a better choice overall. You surely wouldn't be unhappy with it.
a lot of times, if you pile in the baseboard, you can even run it at condensing temperatures (if you are willing to sacrifice responsiveness, which you should). However, it's not radiant heat. It's convective.If it's a gut rehab, radiant ceiling can do it a similar price and lower temps though, typically. Panel radiators can be a great choice too.But it is a dirty little secret in our industry even from many installers that baseboard doesn't have to be a high temp method.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
However, it's not radiant heat. It's convective.
My plumber/heating guy always said that, like it's predecessor, steam radiators, baseboard was both, radiant and convective. What gives? Is baseboard primarily convective with some ability to radiate?
So what are the advantages of running baseboard at lower temperatures? And how much bigger, in percentage of additional feet of run, would the system have to be?
given Cali ....can't you just get by w/ a room heater, or two ..??the price on Radiant will be shocking ...
Yea eventhough its Cali it still gets cold enough in the winter to need real heat-SWMBO is from southern CA and she requires the house to be actually warm in the winter.
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Steam radiators... as the name "radiator" might imply.. are primarily radiant in their heat output. Though they are very high temperature, so they do heat up air enough to cause convective currents as well. They have lots of surface area meant to emit radiant energy into the room.Baseboard has the surface area but most of it is facing each other (fins) so the radiant component is greatly lessened. However, it drives a good convective current. And of course there is *some* radiant benefit, or the floor near a BB unit wouldn't feel warm. But it's primarily convective in nature. So it heats air that has to heat the room. Long term, steady state in a well sealed and insulated envelope, that may not be a problem, but IN GENERAL radiant heat transfer is more comfortable.Low temperatures, though, are typically more efficient. Especially if you are using condensing technology. They can also utilize more heat sources (think geothermal, solar, etc). It can mean a heck of a lot of extra baseboard. But as a RULE OF THUMB that means nothing on a particular project, I often find the baseboard most people have installed in their homes can run at 140 or so as is, and in modern well insulated homes, maybe even as low as 120 or so. If it's hooked up to a cast iron boiler without intelligent control, below 140 isn't helpful. but on modern boilers, or with mixing, it can mean good things for efficiency and comfort to run lower.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Thank you for the excellent answers.
So I still have this question, what type of professional would I need to employ to get this heating system figured out and designed intelligently. I'm not talking about a rule-of-thumb type 'design' I want the actuall calculations done-uh what are they again, manual j and one other?
Is this something that I would have to contract with a mechanical engineer for? Don't have a lot of faith with the local HVAC guys, at least the ones I've had dealings with. Everyone else I know that has had a heating system installed around here has nothing but bad things to say about the contractors they used...
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Like one of the last posters said, radiant is very expensive. I think if you got a few estimates, you would quickly forget the radiant option and move on to something else.What type of fuel are you going to be using, natural gas, oil, propane, etc. Also, what type of access would you have for ductwork?If you have access for ductwork, my first choice would be hydro air. Its a very good heat but still has the ductwork for you to add AC on now or later. I would run hydro units for the upper floors and either a hyro unit or baseboard for the basement. If you have limited space for ductwork, you could do a high velocity unico unit, those are more expensive than the conventional though (albeit better heat and cooling).heres a few links that explain hydro air.http://www.santaenergy.com/Residential/HydroAir.htmlhttp://www.boucherenergy.com/hydro/index.html
Call Alan Forbes and pay him to do a few hours of consultation if you are seriously interested in radiant heat. He doesn't do the work anymore but will give you a very good idea of the cost and feasibility. And get a copy of Modern Hydronic Heating by John Siegenthaler (+$100 at Builder's Booksource in Berkeley)...you're a scientist?..you'll love it as bedtime reading.
Edited 8/10/2007 8:57 pm by sawduster
Yea I need to hit up the builders bookstore again. I know JLC has a guide that is supposed to cover HVAC but I don't know how useful it is.
Who's Alan Forbes? I'll gladly pay an expert to consult on this.
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
Manual J is used to figure the heat and cooling loads. Manual D is used to design ductwork. HVAC-Calc is a relatively low cost program that will do both, and you can get more info here: http://www.hvaccomputer.com
The program is not as specific with every single minute detail like a manual calculation or some of the other programs out there, but it gets the job done.
The other half of the story about "unhappy HVAC customers" is you get what you pay for. Yes, there are shady contractors out there, but contractors have also been programmed by price shopping customers to bid/install low end work to keep the price down.
If your climate is mild enough, a ductless mini-split heat pump might do the trick.
Radiant heating is nice and relatively cheap to operate (especially with the new low temp condensing modulating boilers), but there is no getting around the cost of installation. A system with an indirect fired water heater and zone controls for the rooms is even more money. Unless labor costs are *really low* in your area, I would be surprised if your staple-up radiant retrofit job came in under $25k for a basic, simple system.
Fin tube baseboard might be considerably less money, and Myson offers some really nice radiant panels and radiators.
High velocity manufacturers (Spacepack, Unico, High Vee, etc) all offer options to use a coil and hot water to provide heat. Unlike a straight radiant job, this option offers the ability to add cooling at some point. The high velocity systems must be installed properly to avoid excess noise.
Dan Ski ...issa Smart Guy ... :>))
Hi Dan and thanks for replying,
WOW $25,000 smackers is a lot of dosh for a radiant retro-fit install...dang...WOW... I knew that if I was going to try for a gshp that was going to cost additional but that is a lot of money....wow...
I was thinking 3 story place ~ 1000sq ft on each floor zoning it per floor made sense and I need a new hot water heater-this is the type of install that you are saying will cost considerably more than the $25,000..here in the SF bay area labor costs are not small...
Well since I think it looks like I got the space to easily run ducts to all parts of the house it looks like that's the best way to go-that and I'm not going to say that we will never want AC.
That HV-calc program looks pretty interesting with the manual J and manual D calcs...I can get a good idea of what the house will really need before I try to find an HVAC guy to do it for me.
I agree that most HO's are cheap and get what they pay for. I have no problem paying for a higher quality job-as long as it actually is a higher quality job.
This might be a case where we have to do it ourselves to make sure its done well at a reasonable price...unfortunately that's why we do all our own work (besides foundation and roofing), because we can't find someone who will do a better job.
I've poked thru some books at the builders book store and I do understand the physics behind planning ducts (I think) can you reccomend a source where I can learn more about the right way to run-plan ducts?
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
I personally know someone that had a staple-up radiant retrofit job done with a standard 80% efficient boiler, mostly PEX mains, PEX floor tubing (of course), no outdoor ambient boiler controls, one cheapo thermostat and no zoning at all... about 1600 SF on the first floor and 300 on the second floor, and the job was just over $20k.
Indirect fired water heaters have a high initial cost (but last a long time) and require additional boiler controls, piping and a mixing valve (floor is low temp and water heater is high temp).
A high quality, high velocity forced air AC system plus a hot water coil will likely run the same price. A fully modulating condensing boiler with outdoor reset controls and an indirect fired water heater will give almost limitless hot water, long life and relatively inexpensive operation.
The "best" standard power vent water heaters are around 62% efficient while a condensing modulating boiler approaches 98% efficient. Big difference.
Even a top of the line standard forced air heat and cooling system will be less than the high velocity stuff, but the ductwork will be bigger- and that is a whole nother set of problems.
For a ballpark GSHP price, take the price of high efficiency forced air equipment and add the cost of drilling the wells. In my area, it is one 200' well for every 12K btu of heating, at a cost of about $2500 each.
Unfortunately, things like radiant and GSHP have a very high initial cost, but that cost is recouped long before the life of the home is exhausted. People do not want to outlay the $$$ on the front end, but seem to have no problem paying for standard efficiency as a cost of ownership. Must be the "I'm not gonna be in this house for long" syndrome.
The industry standard for low pressure residential duct design is Manual D offered by ACCA. Google will help you find it.
If your climate is pretty mild, I still believe that the ductless mini-split heat pump offers the best bang for the buck- especially at only 1k SF per floor. There are systems available that use one condenser (outdoor part) and multiple indoor parts (wall or ceiling mount), and they are very quiet. Minimal indoor destruction is another added bonus.
Base board hot water is very responsive and easy to maintain. The only disadvantage is lost floor space along the outside walls. Because of you mild climate, you do not need alot of radiator length. Hot water boiler also make the best (cheapest) domestic hot water.
I'd encourage you to think in terms of a system that's a combination of parts. Radiant where it's easy to install, hydronic or electric baseboard units to supliment low performing underfloor radiant or rooms that are too difficult to retrofit with radiant, some small ducts to circulate air between the floors and rooms, perhaps a small heatpump unit for a few upper or sun facing rooms to be both heat and AC.
An undersized forced air system combined with an undersized hydronic system may be the best of all worlds. You get the warm floors and ability to cool the rooms during the hotest days and additional heat for the coldest. If you have alergies it also is a great way to have clean air with the addition of a good filter and simply running the blower constantly at a slow speed.
There's nothing wrong with a heating system that only keeps up 70% of the time as long as there are suplimental heating sources that can be used in addition for the other 30% of the coldest days.
Beer was created so carpenters wouldn't rule the world.
Lessee -- has anyone suggested a match yet? :)
If by "radiant" heat you mean in-floor hot water (and if that's what you mean it's a misnomer), it'a expensive and troublesome and probably not what you want for most of the house (though you may like it in, eg, a master bath).
Your basic three choices are forced air, hot water, and electric resistance. Hot water can be with in-floor loops, baseboard, or old-fashioned radiators. With electric you can have in-floor, in-ceiling (closer to true "radiant"), and baseboard.
If indeed there is a good-sized chase for the ductwork, and all the ceilings are out, and the framing gods are with you, forced air is probably cheaper than hot water, and likely to be as efficient if not more so. Plus it's lower maintenance than hot water and works well for air conditioning. Modern zoning controls eliminate most of the "hot up/cold down" complaints.
Used to be retrofitting hot water was a PITA, but now, with flexible plastic pipe, it's about like stringing wire, and would be the obvious choice if you didn't have things torn totally apart or had other reasons why ductwork was impractical.
Electric resistance heat is kind of the fallback when nothing else works. More expensive to operate, but cheap and easy to install. Though probably not wise to do the entire house with it unless you super-insulate, sometimes it makes sense to use electric resistance heat to augment other techniques in areas that are hard to reach with ductwork or pipes.
It's important to understand that you don't heat a house, you heat the walls. If the walls are warm the interior is warm, assuming halfway decent attic insulation and a reasonably sealed (if not actively heated) basement.
It's important to understand that you don't heat a house, you heat the walls. If the walls are warm the interior is warm, assuming halfway decent attic insulation and a reasonably sealed (if not actively heated) basement.
Isn't the point of radiant floor to heat all the objects in the room?
True radiant heat, yes. And that's wrong. You need the heat at the walls. Heat everything evenly and the walls will be cold, the center too hot.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
You really dislike radiant floor heating, don't you?You must have been burned by a real hack installation at one time. No pun intended.SamT
Don't dislike it, I just think it's oversold. And it ain't "radiant".
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
How is calling in-floor "radiant" a misnomer?Just because it has some convective components doesn't mean that it's primarily anything other than radiant transfer. Sure, it may not be radiant ONLY, but it is definitely primarily radiant in nature.You can also do hot water radiant ceiling, it's not an electric only method.I fail to see the truth in your "heating the wall" statement. Floor loss and ceiling loss while small are noticeable, and your "heating the wall" statement completely ignores infiltration which can and often does occur at walls originally but can transmit into other areas of the home as well through the framing, or can occur through any other penetrations (say, ducted ones) as well. Also, Part of the reason baseboard is often less than ideally comfortable is especially coupled with setback control strategies, surfaces other than the wall are allowed to get cool. They aren't technically "heat loss", but they are drawing heat from your body until they are reheated.In a very well insulated home, with a continuous heating strategy though I'm with you that many methods can be very comfortable indeed, and that MOST loss is at the walls/windows, most of the time. I still don't see why that's important though. Most of the actual heat loss may not be through the floor, but keeping it at room temp instead of room temp minus several degrees for stratification still makes quite a difference in operative radiant temperature in the space and whether it draws heat from your body, and at what rate it draws that heat. Or do you not see a difference between a 60 degree and a 70 degree floor radiant temperature plane in terms of its impact on occupant comfort?-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Well, first off, you have essentially zero loss through the floor/ceiling communicating with another heated space. And in a structure such as this, where there is a (mostly) sealed basement, there's very little loss through the floor. Insulating a ceiling, if there are reasonably few penetrations, is generally straight-forward -- you can get 12-24 inches of cellulose cheaply and easily in most cases.The walls are the difficult part -- thin, with frequent window and door penetrations, and highly subject to air infiltration.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I understand: I don't agree that you're comfortable if you just heat a wall though. With most heating methods, stratification alone will guarantee that the floor is well below optimal conditions for thermal comfort.That is where most of the loss is: agreed. It is not the sole determinant of comfort though.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Yeah, and if the floor is comfortable, stratification will guarantee that the head is uncomfortable. Airflow is the best way to address that problem.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
?Why would that be best? driving airflow reduces thermal comfort. Adding ceiling fans to a radiant system, for example, is less comfortable.. you introduce a chilling effect on the skin.Using a primarily radiant method from the floor especially results in very little stratification and nearly none at human occupancy heights in most homes... maybe more, if you have very short ceilings. Even radiant ceiling will result in more comfortable floor temps than any convective method.The only time a warm floor guarantees an uncomfortable head is if you are warming the floor with a primarily convective method, so you are overheating the entire space to get the lowest level of stratification up here. Sure, in that situation, airflow helps. But you're making strange claims regarding radiant panel heating here that do not bear up in the field, nor in the research.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
"stratification will guarantee that the head is uncomfortable." And this relates in what way to peoples favorable raves about radiant floor heat?I don't think I've ever heard of or read about anybody with RFH complaining about comfort without also complaing about the hack installation. And I personally know of two situations where the people love it and definately have less than optimal systems.One is a small commercial chicken processing plant, maybe 500-1000 sqft of floor, with several chiller sinks, heated by a 20 gallon electric water heater! It was cool but still within the comfort range in a tee shirt.The other was a large, tall, storey and a half with walkout. The basement had one 450 sqft zone and a couple of smaller zones. The upstairs Baths each had their own 120 sqft zones. The pex was loosely stapled under the subfloor, truss joists, and the joists were allowed to act like a whole floor plenum! There were no balancing valves at that time, although I strongly reccommended them against the advice of the HO's best friend, the electrician. All powered by two 50 gallon propane WHs.While it takes alot of knowledge and engineering to get efficiency from a hot water RFH system, it's also hard to NOT get comfort.SamT
Edited 8/13/2007 11:31 am by SamT
Just an observation:
We put water radiant in an addition to our house because it was darn near impossible to get ducting from our forced air system to the addition without wasting a LOT of space for ducts.
I'd give my left nu . ., (er, nevermind what I'd give) to have radiant in the rest of the house now. You can set the thermostat 10° lower and be more comfortable in the radiant addition than in the forced air main house. And, the temps are WAY more even throughout the space with radiant. No hot spots near registers, cold spots on the other side of the room, hot ceilings/cold floors, etc. You can keep yer airflow -- give me radiant every time.
Now, A/C is a different story. Still need my forced air for that.
IMHO, it is not possible to oversell radiant for heating. Best there is, comfort-wise. YMMV.
Mike HennessyPittsburgh, PA
You know if you are going to have to run ducts for AC its seems like a lot of unnecessary expense to do a seperate radiant heating system. If ya got the ducts why not use them? Can you use the same ducts for ac and heating?
Daniel Neumansky
Restoring our second Victorian home this time in Alamdea CA. Check out the blog http://www.chezneumansky.blogspot.com/
Oakland CA
Crazy Homeowner-Victorian Restorer
guess it depends on what you mean by "unnecessary".Radiant piping never lines up with dust over time. and while the above poster's experience might be a bit more extreme than most (most of my clients are not turning down their thermostats ten degrees after going with radiant) radiant heating does provide a comfort level that is very hard to match in a typical building with any FHA system. Any hydronic system also does it with significant efficiency gains, if not at the heat source, then in distribution efficiency.Payback? Maybe not. Then again I'm not sure how much duct cleaning costs ;)-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
If you are interested in coolng rather than air conditioning, then check this out:http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=346135&_#Message346135
Edited 8/15/2007 2:31 pm by sawduster
Not very practical for a city home.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
I might put in electric baseboard in your climate, it's cheap to put in. Not very cost effective to run, but then again, you may not need much heat.