09 May 2010

What the heck is "Hydronic" heating?

We told our HVAC company we were open to (even likely to favor) innovative ideas. The center piece of their solution was Hydronic heating. That, of course, had us googling like crazy people. A quick google search on Hydronic heating yields lots and lots of information.......about “hydronic radiant heating.” Hydronic radiant heating circulates warm water through small pipes or tubes in the walls or floors of a house. The resulting warmth “radiates” into the room. It's a great system for some applications but we realized quickly it made no sense for us. The time to put those little tubes in the floor and ceiling is when you build the house. You can put them in as a retrofit but it means tearing up a lot of the house and that wasn’t what we had in mind.

A few clarifying emails to our HVAC friends quickly confirmed that Radiant Hydronics was not what they had in mind. They were instead proposing a forced air solution using a hydronic heat exchanger. It turns out, this is not such a new solution. Most commercial heating systems are based on this idea i.e. a boiler and forced air. You’d think there would be lots of information on this subject as well. Turns out that is not the case. There is almost no information on this kind of system, how it works, how efficient it is, when to use this vs. a standard heat exchanger. So, check out our Hydronic HVAC page to see the explanation we’ve put together.

The Proposal (s)

The HVAC company came back to us with a Chinese menu of options organized into three scenarios.
Scenario 1 - Basic HVAC Upgrade
AC sizing
Thermostat
A Hydronic Heating and AC System

Scenario 2 - Energy Upgrade
Everything in scenario 1
Per room airflow calculations
Duct sizing
Duct Repair and Resizing
Replace Attic Insulation with Foam insulation
Heat Recovery Ventilator

Scenario 3 - The Rock Star Upgrade
Everything in Scenario 2
Zone Balancing
New Duct Work
Foam Insulation of the Crawl Space Below the House
High Performance Registers
Web Linked Programmable Thermostat
Condensing Tankless Gas Water Heater / Boiler

Naturally, we liked scenario 3 but scenario 2 was closer to our budget. Now we needed to understand better the systems being proposed and the tradeoffs between them so we could decide on a scenario that best worked for us.