I think I would try to salvage what I could of the hot water baseboard system and go with mini-splits for the rest of the house. By adding the mini-splits you can heat very effectively with them as well as being able to get your cooling and dehu.

It is extremely difficullt to add ductwork to a home. You loose space. As well, the mini-splits are individually zoned and significantly more efficient. Fujitsu and Mitusbishi are the two biggest brands in your area. Where are you "outside of Boston"?

Thanks for the feedback. The house actually had existing A/C ducting running down the small attic space in the ridge of the roof. The ducting needs to be augmented for the new rooms, but seems all the rooms could be heated/cooled from above without losing any usable room space to install ducting.

The house is in the Weston/Wayland area.

I'm not all that familiar with mini-splits, although I've seen the them used for A/C in other countries. I'll try to read up on them.

I would agree with Jackfre. ThatâÂÂs good advice. My experience with home like yours has been keeping the hydronic system and integrating it into a geothermal, all hydronic heating and cooling system without ducts. Those that have done it are very happy with the results, although it is expensive.

From a technical point of view your contractor may not have given you bad advice either but it seems your preference is for hydronic baseboard radiant. You could heat the newly renovated area with hydronic in-floor radiant as well. One question for your HVAC guy is what water temperature will you need with what heâÂÂs proposing. The higher the temperature the more energy youâÂÂll consume. Few options will require a lower water temperature than your cast iron rads but in-floor radiant could be one of them depending on spacing between pipes.

What source of energy are you now using for your boiler, how old is it, what size and efficiency is it?

SR

The boiler is a Viessmann natural gas boiler. A Vitodens 200 W, and the EnergyGuide sticker on it pegs efficiency at 96.1, with I think BTU output of 127,000. It was installed approximately 4 years ago.

It is good to hear I'm not out in left field wanting to keep the rads. I guess at this point it is just a matter of do I want to deal with tearing up the 1st floor to get the rads' input/output piping to the basement and possible expense if I need to buy significant additional length of baseboards.

I will definitely ask about the water temp for the hydro-air system. Is there a rule of thumb for what the rads require?

Excellent boiler! Mess should be minimal to install piping for a hydronic system. You may be able to find a local source of reclaimed/reconditioned rads similar to or exactly as you have now at a reasonable price.

Btu output of any rad will depend on water temperature and flow rate. You will have to consult with the supplier for a chart of Btu output verses water temperature for a given length of rad at given flow rate etc.

Since you are renovating, you have the opportunity review the configuration of your piping (primary, secondary loops, reverse return, zoning, etc.) as well as âÂÂOutdoor ResetâÂÂ, variable speed pump(s), zone valves, thermostatic temperature controls at the rads, automatic air & dirt elimination, water chemistry, etc.

Modern hydronic systems today are VERY efficient - and NOT your parentâÂÂs hydronic system of the 60âÂÂs! Remember, per given volume, water is 3,500 TIMES more efficient than air at transferring (moving) heat! The Hydro-Air system will also require a large blower fan motor whereas an all hydronic system only requires a very small, quiet circulator because of the efficiency of water as a transfer medium.

This is your opportunity to âÂÂGet It Rightâ - take the time, as the energy savings and comfort factor can be huge!

Think Water!

SR

Here is a link that might be useful: Steam Experts