PEX retrofit on 100 plus year old house

Bob Bona_4

house might be a bad candidate for radiant. Infiltration would be the killer (high floor load). An above floor dry panel system may get the job done but I would take a hard look at a radiant load and design before I pull the trigger.

Kpc has a great solution with the panel rads or even the CI ones. Homerun system. No muss no fuss. All controllable from the manifold station, and TRV's would be the icing on the cake.

rich on heat

hi
Can PEx for heat with an oil fired furnace actually be efficient or more efficient than using baseboard or radiators? the pex would be installed under floors over an unfinished basement - with a dirt floor and in one room - over a dirt crawl space - the basement is a combo of brick and stone walls that see frost in the cold winters of vermont.

if pex could be done to achieve an efficient system - how would this be done? what type of insulation and such would be necessary to keep the circulating water hot? without continual running of the boiler?
thank you.

kpc_44

well my current home...

is 200+ yrs. old... it had a forced air/ oil fired system in it for many years. the olny way heat got to the 2nd and 3rd floor was by convection... hot air goes up. Although if you did not kepp your doors open you froze!
I pulled out all the duct work and ran homeruns of 1/2" PEX tubing up through the walls to panel radiators. They are driven by a Buderus 115-21 oil boiler w/ a Tekmar reset control. They work well I have added blown rock wool to the 1st floor walls and sprayed the 3rd floor walls and ceiling w/ urethane insulation. My heating& Hot water bill is reasonable for a 2800 sq. ft. house in NH. about 7-800 gallons.

kpc_44

I see from...

your other post your situation. I just did a home like your for someone else. They had rads that they reused. I did the HR in PEXa to a manafold and ran the system off a reset control (Taco PC 700)... It runs great. I wish I had all those rads you have. I would have done that w/ my place.

Rich Kontny_3

Different animals

The panel radiators are a completely different distribution method than in floor or under foor piping. I would recommend the panel reads as the underfoor in an existing home with thick floors (or floor covering) will restrict proper heat transfer,

Most pex has high temp restrictions of about 170 degees. Also most wood floors and floor coverings like to see temps less than 150 degrees (maximum 150 in other words)

If you do not have existing rediators or baseboard you need a complete heat loss done along with options regarding the distribution choices you have.

This should be done by a reliable firm or professional well schooled in hyronic heating systems. The money you spend up front will will be well spent! You can always get three competitive and comparable bids when you take the time initially to have a properly designed system.

If you solely rely on the contractors for design you may not be able to compare apples to apples (if you will)

Mark Custis

Yes

Yes. I would use pex.

rich on heat

what is a TRV please?

rich on heat

hi - thanks to all for the wonderful information.

the old radiators are great to have. was lucky to find them. yesterday i was driving somewhere and spotted a six foot long steam radiator someone had left on the curb. much to the dismay of my companion we dismantled and picked it up! lucky find. although this one is steam only without work. most of the radiators i have are good for hot water.

how exactly did you pipe the radiators - ? as a one pipe system or two and what did you use for the entrance and exit valves on the radiators please?

what type of boiler did you use for the system?
thank you again!

rich on heat

hi thanks all for the info.

yes the infiltration and thick floors were a concern. warm feet but at what cost?? the wood floors are over an inch thick and the basement is never going to be well insulated by todays standards no matter how much work i do. short of lifting the old house and building a new foundation - it will be the shortcoming of this home. and we are not going to jack the house up........

so radiators will be a better more efficient source of heat vs the radiant?

kpc_44

in both....

cases they are piped to a circulator, then to a manifold(supply and return each w/ 6 ports. With the cast iron rds the valves are piped below the floor w/ steel then adapted over to 1/2" pex. Both boilers are Buderus G115-21 boilers. do you hatloss numbers 1st....

rich on heat

did you do the urethane or have someone else do it? that is an expensive proposition - but the way to go these days. 800 gallons a year for that size house in NH is impressive!

kpc_44

cast iron..

rads are radiant heat... just not radiant floor.

Bob Bona_4

thermostatic

radiator valves. Think room by room temp control via a dial on the radiator. The system has water temp and flow controlled by boiler controls/constant circulation (simple version), and the TRV's meter how much "juice" each rad needs.

Saa-weet!

Bob Bona_4

radiant

floor could possibly do it, again, an accurate design analysis will show it. Your application almost dictates an above the subfloor product like Uponor QuickTrac, or possibly gypcrete. Don't rule it out, just learn the extent of the home's "shortcomings" on paper before you do, and see if those products will work.:)

Either radiators or radiant floor is "efficient" in terms of what it takes to make you comfortable. It's about what will do the job in YOUR house, your budget, and what you want to look at in the room.