How many heat zones can I afford?

JerseyJon

I have a 2 1/2 story four square outside of Philly with circulated hot water heat. There are two main loops, one to the front of the house and the other to the back. There are separate risers for almost every radiator, so I have some flexibility in figuring out how to zone the old lady (1911). I have first floor living space, bedroom space used daily and guest space used infrequently. So three zones might be the way to go. Then I start thinking the kitchen and living room and dining rooms get used differently and wouldn't it be nice if they each had their own thermostat? And is the bathroom really on the same schedule as the master bedroom?

So, my question is, what are the economics? What are the costs? Does a 4-zone system cost twice as much as a 2-zone setup? Or are the costs higher for the controls? I have a new boiler, but I'm guessing the controls won't handle multiple zones. Can someone throw out a rough range of prices for controls and valves?

Also, another post mentioned a setup using an outdoor reset, TRVs and just letting the circulator run. Would that be more or less expensive than valves and wired thermostats? Thanks for any help.

JStar

Zones

Your ability to properly zone starts and ends with a heat loss calculation and accurate boiler ratings. The smallest zone should be no smaller than the lowest firing rate of your boiler.

Rich_49

TRVs

for your radiators would be the best option considering your concerns .  Every room / rad would operate independently of the others , comfort would be optimal and should you decide to keep rooms at different temp ranges when you change the setting the response time is nice . Wireless zoning and efficient as hell .  TRVs and bypass fittings are relatively inexpensive and require a bit of elbow grease maybe to retrofit but feel worth the investment in time and funds . You should be able to utilize an ECM circ also really lowering your electric usage .You get to keep that old house style and have modern efficiency ratings system wide . We cannot really throw out numbers here but check the following for price and availability .

 http://www.caleffi.com/usa/en-us



 Are you in Jersey or Pa ?

JerseyJon

Interesting question

Joe, when I first came across the heat zone idea, it made me wonder. If I'm reducing the heat and heat loss in some portion of the house, at what point does that make my boiler oversized? Or as you put it, at what point is a zone too small? If I had a powder room with its own thermostat and radiator initiating a cycle that would be bad. So I'm pretty sure I get your point about lower limits on zone size.

Heat loss is a moving target. My house is a major fixer upper with ongoing insulation, caulking, weatherstripping, storm doors etc. I tried to size the boiler for where I expect to end up in a couple of years. I guess I should do the same to calculate zones?

How do I find the low end of the firing rate for my boiler? I only remember looking at the high end when we sized it. An outdoor reset would lower the temperature of the water at times. Does that factor into the low end calculation?

Rich, I know you can't give estimates on here. I'm just looking for some rough guidance as get started. Does it generally cost less to zone a house with TRVs than wired zones? Maybe someone just had their house done and can say it cost less than x per radiator or per zone. I'm in Drexel Hill PA, but am a proud native of Cape May NJ. The ECM circulator sounds interesting and goes on my list of things to research along with the outdoor reset. Any idea how long it would take to recoup the ECM cost? I have no idea how much juice the circulator draws.

JStar

Cost

Without getting into exact numbers, TRV's are going to be more expensive than just a few zone valves. How much more? Let's just say that each TRV is close to the same price as one zone valve.

Rich_49

Comfort

I guess you could put a price on it but when you design for comfort efficiency follows . Yeah , the TRVs will be a bit more expensive but control over all areas even within a single room can't be beat .  The Taco bumble bee is not an expensive item per say , recoup could be 1 - 2 years mathematically .