Category Archives: AC and Hydronics

One of the advantages of our basement demolition and excavation efforts was to clear out decades of plumbing, hydronics, and electrical (especially electrical – we had three generations of technology down there, from some original knob-and-tube, to wire conduit, to Romex), and start anew with a basement utility hub that wouldn’t eventually burn down the house.

The additional benefit of the excavation of the southeast crawlspace, specifically, was to allow the boiler (which would supply hot water to the radiators and heated floors), the hot water heater, and the electrical panel to be consolidated in one area of the basement. This would allow maximum utilization of the remaining area. This crawlspace area was barely usable in the pre-reno house. Some pics of the basement before are provided below.

Here’s the old boiler and hot water heater, located on the west side of the basement (really, the only place they could be, due to the limitations in this area):

This is an even better picture of the mayhem that lay dormant in our basement. Looking through the doorway, you’ll see the old electrical panel, located in the quasi-exterior area in the basement. Note the crawlspace area between the door and the panel – previously of limited use, this will be the home of the new home utility hub. The plumbing stack in front will remain where it is (as seen in https://wolfestreetproject.com/2012/04/09/insane-in-the-main-drain/).

Regarding the tangle of old wiring, plumbing, and hydronic elements in the old house, check out this action, which includes hydronic lines to nowhere that were capped off when radiator locations changed during previous renovations:

All of this came to a satisfying end with the demo work. Our contract with the GC specified that everything down here would be eliminated and reinstalled and replumbed and rewired anew . . .

After demo and reconstruction of the expanded basement (https://wolfestreetproject.com/2012/03/15/slab-happy/), the first step of our new power plant installation was arrival of the boiler and hot water heater. The boxes obviously contain these items; the equipment already mounted to the block wall is the manifold for the hydronic lines, which we’ll see later:

These elements will actually be located in the space that previously was occupied by crawlspace, so, bonus in space utilization, eh?

To the right of the boiler and water heater will reside the “heavied-up” electrical panel (from 100 to 200 amps) to support more electrical. At this point, it’s just the termini of a bunch of electrical cables.

Here’s a photo of the water heater and boiler after initial installation. There’s a lot more to go before this area is complete, including installation of the electrical panel, which is still AWOL at this point. The grey canister is the new expansion tank, which previously was a large, green drum about 5x the size that hung from the joists above the work bench. The old tank needed to be drained periodically, and so we’d have to screw a hose onto it and run the hose across the basement to the utility sink. The worst part was that there was no venting on the drum, so the water that had built up would drain for hours. The new expansion tank has a rubber bladder inside that contracts when water needs to escape from the hydronic lines, then expands to expel it back again when the expansion need abates. No muss, no fuss.

In the photo below, the electrical panel has been installed, as well as additional electrical lines (and the underfloor heating at the back of the house, which we’ll see in more detail). Jim, the lead for the mechanical sub, is doing some install work down here the day the picture was taken. (They did a spectacular job with installation of both the hydronic infrastructure and the AC components.)

Another new development at this stage is installation of the electrical panel (sans connections).

This is what’s lurking behind there – a manifold to route hot water from the boiler to three zones in the house. At this point, there’s only a few lines coming off it, but it’s going to get really crowded.

The three climate zones in the house are:

• The second floor, heated by salvaged radiators in each of the two bedrooms, as well as under-floor electrical heat in the two bathrooms,
• The first floor, heated by under-floor hydronic heat in the vestibule and kitchen, and by two small (really, really small) radiators in the powder room and the area at the top of the stairs the basement, and
• The basement, heated by radiators in the office area and in the unfinished area.

In addition to controlling the radiant heat (as well as the AC) via thermostats on each floor, there are failsafe controls directly on the trunk lines for hot water heading into each zone. These three brass, manual controls can be seen on top of the copper pipes in front of the PVC drain line and above the expansion tank.

The red tubing feed two types of radiant head elements – radiators (before which they are connected to copper pipes) and under-floor heating. In the photo below, you can see some of this latter heating approach.

Here’s a view of the actual heating elements. Insulation beneath the radiant elements will be installed later, with a reflective side against the metal plates.

Unlike the new basement area, where we had brand new, virgin framing to work with, the under-floor heating in the front of the house had to be run through existing space. The guys had to rip out drywall and install the radiant plates and hydronic lines above the built-ins, which we’re retaining:

This is pretty much the apex of hydronic lines. The red ones heading up in the photo are supply and return lines for the master bedroom radiator and under-floor heating in the kitchen.

Late in the infrastructure game, the gas lines were finally run. We had to upgrade our meter to a high-pressure line to accommodate the additional appliances. Gas will be required in the renovated house for the following:

• Hot water heater
• Boiler
• Dryer in the basement
• Stove
• First-floor fireplace
• Master bedroom fireplace (future)

Similar to the manifold approach to distribute hot water for radiant heat, a manifold was installed to distribute gas to the appliances throughout the house:

The yellow gas lines shortly thereafter began to infiltrate the basement. Here’s a shot after the lines were run off the manifold. In addition to the new lines, insulation in the first-floor joist bays has been complete at this point. The area’s dense with equipment, electrical lines, hydronic lines, and gas lines, now that the basement utilities have reached critical mass, but we’re happy it’s all in once place, compartmentalized from the rest of the newly excavated area (which will allow for storage of more bikes, of course . . .).

The interior framing is complete, so house infrastructure installation is on deck. The infrastructure components include mechanical, plumbing, hydronics, and electrical. They get installed in that order, since the vents for the  mechanical are the largest component, then the plumbing drain lines, then plumbing supply lines, then hydronics, then electrical cables. It’s a lot easier to route 3/4″ copper pipe around already-installed 10″ AC vents than trying to fit these vents in between framing and plumbing elements if they were done in the reverse order . . .

The mechanical systems in newer houses typically includes an AC/heat pump that provides both cooling and heating through the same vents. Our house originally had radiators for heat (requiring a hydronic system to supply and return the hot water); separate AC vents and a mechanical system was added later to complement the radiant heat. Once you have a house with radiant heat, you never want another system – trust us. So, we’re replacing and optimizing this system. This post focuses on installation of the air handler and air conditioning vents. Future posts will cover the other infrastructure elements as they follow, in order of declining diameter.

The first thing to get installed was the air handler at the top of the stairs on the second floor. The guys from the mechanical sub started to set things up on a Tuesday:

Vent components on the second floor ready for installation. The insulated units go above the rafters on the second floor, where the environment won’t be conditioned, like the interior spaces. Although we’ll be doing foam insulation, which has a wicked bad R insulation factor, and a white membrane roof, the space above the rafters still will be hotter in the summer than the rest of the house. (Plus, code requires this, so, insulated vents it is.) The bare metal vent will be installed between the second and first floors to supply the first floor with conditioned air in the summer.

AC terminal units awaiting installation. These will branch off of the larger vent units shown above.

Insulated vents get installed in the master bedroom, awaiting registers during later stages of construction.

Venting in the master bedroom. This is routed directly from the air handler, so we’re hoping it won’t freeze us out in the summer . . .

Venting over the rafters in the guest room from the air handler to the south (right). Although the vent in the foreground serves the guest room, there’s another behind with black insulation that leads to a ridgid vent pipe in the northeast corner of the room.

The articulating, insulated vent at the back leads to a rigid vent which heads downstairs . . .

. . . to this articulated vent and opening for a register in the vestibule ceiling on the first floor. The reason for this routing is that, because we left intact the original, east-west oriented joists between the first and second floors at the front of the house, we can’t tie the AC in this area to the main supply line that you’ll see below.

This vent-o-vestibule is just a side show for the real venting process for the first floor. The supply vents from the air handler at the top of the stairs on the second floor immediately split into two major trunks. One heads up through the rafters and supplies the second floor; the other heads immediately down through the floor above the powder room and supplies most of the first floor. Here’s a view of the complex routing of supply and return vents above the powder room, as they penetrate the second floor subflooring into the bays between joists on the first floor. From top to bottom, you see the major return vent from the first floor, the major supply vent, and a branch line from supply to a register located in the ceiling between the powder room door and the stairs to the basement:

From the powder room, the supply vent has been installed within the bulkhead created by the glulam beams:

At this point, both the supply and return vents have been run through the bulkhead. The former will then branch out east and west through the bays between the joists to registers in the first-floor ceiling (ignore the drain lines, for now – we’ll deal with that bit of infrastructure in a future post).

From the major supply vents in the bulkhead run branch lines to openings registers in the kitchen. First the target openings:

Then the rigid vents connecting them to the trunk in the bulkhead:

The air handler on the second floor after installation. One return register will be located here, at the top of the stairs (you can see the opening here). Another will be located near the dining peninsula on the first floor (stay tuned for the specifics – could be interesting).

Here’s a view of the installed air handler from the south:

The cooling lines from the air handler head through the roof to the compressor, which will be brought in after the new membrane roof has been installed: