Evan wrote:
"RogerT" wrote:
I am planning a complete rewiring of a house that I own,....

.... One added problem with framing out the
exterior walls is that the house has hot water cast iron radiator
heat, and the radiators are, of course, on the exterior walls --
mostly under windows. So, if I frame out those walls, I will need to
move all of the radiators in about 4+ inches. That means plumbing
work, but since all of the other walls and ceilings are now open,
access to all of the radiator plumbing is easy.

Your ancient heating system sounds like it could be retrofitted
now that you have opened everything up... What are the current
zones configured as ? Replumbing your system so that each
convector is on its own zone using Pex and some zone manifolds
will allow you save energy and have more comfortable tenants...

Since you would be taking apart all the convectors to replumb
them and establish a new thermostatically controlled zone
for each room, it wouldn't be that much trouble to adjust the
cavities they are installed in a few inches...

Better to do this work now while everything is opened up
because it will add thousands more to the bill when your
system eventually fails... Improving the controls for your
heating system combined with the new replacement
windows will result in even more energy savings compared
with heating ALL of the upstairs or downstairs until the
thermostat in the hallway is satisfied... Going the extra
mile and adding insulation to the walls as well couldn't
hurt...

~~ Evan

Interesting thought. Thanks. I hadn't thought about creating zoned
heating. This is a 3-story house which is presently all on one single
zone..

Are you suggesting doing all new pex plumbing to the cast iron radiators,
using a home run system to each individual radiator (or at least to each
room/zone, and a thermostat for each radiator or room/zone)? Or, maybe I
could just create 3 or 4 zones -- one for the third floor, one for the
second floor, and one or two for the first floor (the first floor has a
separate heated porch area with French doors to the house, so maybe that
would be on a separate zone from the rest of the first floor).

If I remember correctly, the type of pex that is used for cast iron
radiators is Pex-Aluminum-Pex (Pex-Al-Pex).

I have seen (on TV) thermostat controls that go on individual cast iron
radiators, and I guess a similar device with a wall-mounted thermostat that
controls the valve may exist.

Once I get started doing these types of projects, I do have a tendancy to
say, "Well, since we're already doing X, now would be the best to to go
ahead and also do Y. So, your suggestion fits right into my usual way of
thinking.

Now that all of the walls and ceiling are open, I'll have to give some real
thought to all of the possible heating and cooling options. I do have a
couple of HVAC people that I trust who I can get to look at the house and
give me their suggestions and the pros and cons for each option.