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Posts from the ‘HVAC’ Category

Overdoing it

A word of advice: never celebrate the one-year anniversary of a one-room renovation project, no matter how ambitious it is. I’m ashamed to say that we recently blew threw that milestone after life did its very best to sap my enthusiasm. But recent weeks have played witness to some honest-to-goodness forward movement. I’ll share details in posts to follow, but among other things we’ve recently passed framing, plumbing, mechanical, and electrical rough-in inspections, re-insulated the walls, purchased appliances, ordered cabinets, and started to install wall and ceiling surfaces.

Even under the best of circumstances, though, I’m a slow designer and builder. I’ve accused myself of overdoing things in this forum before, and now I’m going to show you how that plays out, and why the most mundane tasks take me days to complete.

A couple weekends ago, it was finally time to install a cap for the duct to the new hood vent. Here’s how the last guy to renovate our house did it:

old vent

Nice, huh? Cut a hole through the siding, slap a vent cap over it and get back to the serious business of drinking beer. To this day, this vent leaks voluminous quantities of outside air and is no doubt a bug superhighway in the warmer months.

I knew I could do better.  A lot better.

First, the nerve-wracking portion of the project: I cut a hole in the house:

hole in house

I want to be clear that I was NOT drunk when I cut the hole. But, I’m pretty sure the guy who installed the siding on this side of our house was. The hole and the window are both dead level. The siding is anything but. I could have skewed the hole, but I figure we’ll put new (level) siding on this side of the house someday.

Here’s a closer look at the hole. You can see the old white oak framing, the siding directly on the studs, and the blown-in cellulose insulation, undoubtedly the itchiest and dirtiest material known to man.

hole up close

Next, I primed the edges of the exposed siding to seal them against moisture.

primed edges

Without sheathing, there’s nothing to attach a vent to, so I framed a supporting structure just behind the siding.

back framing

With a sturdy frame in place, I flashed the opening. An aluminum drip flashing protrudes over the siding at the bottom of the opening, flexible flashing tape wraps over this flashing and up the sides of the framing. The tape extends underneath another aluminum drip edge at the top of the opening. Working from bottom to top like this establishes a continuous path for water to drain down.

flashing

After flashing, I built a custom wood frame to support the vent and trim out the siding. The frame has a cap with a tapered top and a drip kerf on its bottom side. The frame has thick wood sides that mimic the nearby window trim. I primed it on every surface and put it in place with stainless steel screws.

frame

With the frame firmly affixed, it was finally time to install the vent cap. I ordered a copper cap with a damper and a bird screen. Yes, I could have bought a flimsy galvanized vent at the home center for significantly less money, but this one will last a bazillion years and look good doing it. I put a thick bead of caulk along the top and sides of the rear of the cap, but not along the bottom to allow any incidental water to drain. The cap was screwed in place with brass screws.

caulk vent

installed vent

After caulking the gap between the wood frame and the siding, I applied two coats of paint. I think it looks pretty good and it’ll keep looking better as it weathers from orange to brown to verdigris.

complete

And that’s how I translate a job that took the last guy a couple hours into a weekend-long project.

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Our haunted house

We’re told that our house is home to two ghosts. The first is that of Jane Hayes, a young girl who died of consumption in 1850. She’s a typical ghost, ethereal and wispy, able to float through walls. The second specter is odd: a cat’s body with the head of a man. The story goes that the face belongs to William Hayes, a physician who kept his offices in The Ordinary House in the 1920s, and who believed that humans were reincarnated in the form of animals. We’ve not yet had the pleasure to meet either of these apparitions, but I’m soundly convinced that we’re haunted by a third ghost, one who is bound and determined to keep us from having functional heating and air-conditioning. After last year’s boiler breakdown and this month’s furnace failure , I hoped that we might be free of HVAC woes for a few years, at least.

But recently, while doing some remedial framing work in the kitchen, I yanked out a piece of wall insulation and was surprised to feel a sudden whoosh of air. I watched as some sawdust on the floor was sucked into a void in the wall. A bit of poking around with a flashlight was all it took to discover the problem.

When crafting return air ducts, particularly in old houses, HVAC contractors will often “pan” joists. That is, they line the voids between framing members with sheet metal to create boxes that collect return air and direct it back to the furnace. The return for the downstairs HVAC systems begins as a sheet metal box above the floor, transitions to a panned joist cavity in the crawlspace which in turn connects to a duct leading to the furnace.

Our HVAC installation technicians probably didn’t stop to think that there’s nothing normal about the way The Ordinary House was built when panning our joists. In contemporary wood construction, the floor structure ends at a rim joist. The floor cavity is separated from the wall framing by subfloor and a 2×4 wall plate, like this:

normal return

In our new kitchen, the walls are partially “balloon” framed, meaning the wall studs are continuous from the foundation up to the ceiling – there’s no subfloor or wall plate to separate the wall cavity from the floor framing. So, for the past year, our HVAC return air has been pulled from the wall vent in the living room, where it’s supposed to, and from the INSIDE OF THE WALL through filthy fiberglass insulation.  To complicate matters, our siding sits directly on the wall studs rather than on top of plywood sheathing. Tiny gaps in the siding placed under negative pressure would have admitted freezing outside air to the return duct in the winter and hot, muggy air in the summer. This means, of course, that the system was working overtime to heat and cool the air. Fortunately, the filter is located at the furnace, so at the very least, the air was being cleaned.

busted return

I’ve filled the gap between the wall and floor framing with wood blocking and plenty of duct sealing mastic and spray foam so I can be certain that the return air is being pulled only from the living room, not the inside of our walls or through the siding.

As the snowflakes fall outside, I hope that I might have finally exorcised our HVAC ghost.

The human-head cat ghost, on the other hand, is welcome anytime.

Polar Vortex: 1, Fancy Furnace: 0

Walking to the back door in the 14 degree chill the other night, I was thinking about how thankful I am to have heat this winter. But climbing the stairs to the bedroom, I noticed that the temperature was dropping with each step. “Strange,” I thought, since the upstairs is usually warmer than the downstairs. The thermostat read 64, though it was set for 68. It’s a good thing we don’t have a “For Sale” sign in the house because I might have nailed it to the door, packed my bags, and hopped the next flight to Las Cabos.

Even without investigating, I had a hunch what the problem might be. High efficiency furnaces wring extra BTUs out of their exhaust air in a secondary heat exchanger. This cools the exhaust to the point that moisture condenses out of it. As a result, our furnace drips condensate year-round. Problem is, if the condensate line freezes, which it’s apt to do when it’s *9* outside, the furnace shuts itself off – at the exact moment you need it most.

condensate ice

The condensate line for the upstairs furnace runs down the side of the house in a fake downspout. Picture this: me, outside in the dark Arctic chill, on my back in a pool of ice, aiming Weezie’s hair dryer at the bottom of the hopelessly plugged condensate line. I promise I’m not as dumb as I look.

frozen condensate

It was an exercise in futility. We slept the coldest night of the year without heat for the second year running. It wasn’t too bad since the warm air from downstairs found its way up to us, keeping the temperature from dipping below the upper 50s.

Fortunately, the fickle North Carolina weather saved us by thawing out the condensate line enough for the furnace to spring back to life the next evening.

The weather man tells me it’s going to be 70 this weekend. And that, folks, is why I live in North Carolina.

Comfort engineering

To kill time during layovers on our recent trip, I read Bill Bryson’s fact-filled exploration of human health and comfort, “At Home“. In the book, Mr. Bryson emphasizes how many of the technologies in our homes are brand new relative to the length of time that mankind has roamed the Earth. For 99% of our history there was no plumbing, no electricity, and certainly no air conditioning.

Consider our home, “only” 259 years old. If I was able to transport back in time and explain to the house’s first owner that one day a device on the wall would allow him to regulate the indoor temperature to a specified degree year-round, he would surely declare me mad and have me committed to the loony bin.

So, in a strange way I’m slightly ashamed to be the one to install central heat and air-conditioning in William Reed’s Ordinary. Even during our grandparents’ lifetimes, it wasn’t a technology that was universally attainable or expected. All the former owners of our house lived without it. In the summer, porches, shade trees and a languid pace made life tolerable. In the winter, fires, extra layers of clothing, and thick blankets offset the chill. When it comes right down to it, living several months without heat wasn’t THAT bad. It was frequently uncomfortable, but life carried on normally, just with thick sweaters on. A colleague of mine once asked his grandmother how folks got along before air-conditioning. Her response: “In the summer, people were hot.” As a society, we could benefit from stepping back to appreciate the everyday luxuries that we take for granted.

I was determined not to let the urgency of our discomfort negatively impact the quality of the HVAC installation. On a job site, the mechanical guys are the ones that cut the big holes, and there’s no end to the devastation they could unleash on a house of this vintage if left unsupervised. I gathered three estimates and selected Newcomb and Company of Raleigh based largely on their reputation and their willingness to think things through before being awarded the job.

There were two simple rules I established for the system’s installation:

1) No ducts can cross the basement – this room has a storied past as a tavern, a happy future as my man cave/grog hall and ceiling beams way too low for any big pipes to run below them.

2) Aside from tactfully placed condensor units and air grilles, the installation should be invisible, with no awkward protuberances in the corners of rooms that betray a lack of planning or forethought.

Fortunately, our estimator listened to these concerns, worked with me to develop a plan that addressed them and assembled a crew that was capable of following through once we pulled the trigger.

A modern heating and cooling system requires an impressive network of connections to bring it to life: supply and return air ducts, a power line, a gas line, a combustion air intake, an exhaust air outlet, a condensate drain, an overflow condensate drain, a condensate pump, a refrigerant line and a low-voltage wire to the thermostat. So even though the indoor units are the size of a large suitcase, the spaghetti of pipes, wires and hoses that surround them eats up a lot of space.

furnace

The Ordinary House is spread out over no fewer than five floor levels. Because of this, we ended up with three separate HVAC systems, with 6.5 tons of cooling capacity and 180,000 btu’s of heating. There were several situations where it simply wouldn’t have been possible to run a duct from point A to point B. So, we ended up with one system for the library, one for the main floor, and one for the upstairs. This setup has two built-in advantages. First, we’ll never be without heat because of a mechanical failure again. If one system goes belly up, there are two more to keep us warm. And second, three systems = built-in zoning. By programming the thermostats to reflect our daily schedule, I can be sure that we’re only paying to heat and cool the parts of the house that we’re actively using.

Based on the amused expression that spread across the HVAC contractor’s face at the mere mention of the words “heat pump” (he likened our house’s walls to the bottom of a colander), we opted for high-efficiency gas furnaces to provide heat. These units run at 96% efficiency, extracting residual heat from their own exhaust, and squeezing 96 cents worth of hot air out of every dollar we spend on natural gas (recall that our boiler was probably running at only half this efficiency). Additionally, the furnaces are two-stage, meaning that they can run in a “low” stage the majority of the time, saving fuel, decreasing wear on the equipment, and preventing too-quick temperature swings.

The air conditioning units are also two-stage. On low, the systems have long, low-speed cooling cycles that are extremely energy efficient. If the units reach their set temperature but detect high humidity levels, they activate a dehumidification mode, running the blower fans at imperceptible speeds, edging the humidity down without over-cooling the house. The swamp-like conditions of the past few weeks have given this feature a workout.

All three systems have 4″ thick pleated media filters that are more effective at scrubbing the air than standard filters. With 200 years of dust floating around, they’ll certainly be busy.

The thermostats that control these systems are fairly simple to use, but employ all sorts of fancy algorithms to determine run times and optimize efficiencies. Given the challenges of regulating temperatures in a leaky old house, the ‘stats have done a remarkable job of maintaining a steady, comfortable temperature without overworking the equipment. Heating or cooling, the systems run in low speed most of the time, which becomes obvious when the energy bills show up in the mail.  Our natural gas bill was halved compared to when we were running the boiler, and it was only heating half the house due to a malfunctioning circulation pump.

The upstairs unit is in the attic, where the temperatures are less than ideal for cooling equipment in the summer. But the steep pitch on the roof makes access a breeze and we were able to run ducts to all the upstairs rooms without any difficulty.  The return grille sits inconspicuously in the ceiling of the hall outside our master bedroom. To get the gas line, refrigerant line and condensate drain to the attic, I bought some extra lengths of downspout from my gutter man and had them disguise the pipes and hoses in it where they run up the side of the house.

downspout for gas line

The downspout butts into the underside of the soffit, and opens directly into the attic. From the street, you’d never know that the downspout isn’t integral to the gutter system. We were fortunate to be able to reuse the electrical circuit from the old attic fan to power the unit. Otherwise, we might have had to tear off plaster to fish a wire from the basement to the attic.

The main downstairs unit is in the old boiler room, consolidated to a corner that I’ll one day enclose as a utility room. Because the crawlspace under the kitchen is all of 12″ tall, we supplied the air to this room through the risers of the stairs that lead to the dining room.

stair supply grilles

Finding a way to return the air for this system was tricky. In the end, I elected to bring it through one of the wainscot panels in the living room. On the other side of the wall, a metal box punches through the floor to the crawlspace below.

return box

When we relocate the kitchen to this room, I plan to hide the box in a base cabinet. Since the return is in a visible location in the living room, we invested in a decorative cast aluminum cover that’s pleasing to the eye. When the grille gets painted, it’ll look tailor-made for the spot.

return grille

The library unit lives in the crawlspace below that room. It has a return grille that punches through the wall of the closet beneath the stairs to the slave quarters.

library return

The same closet provides a home for a supply duct and the electrical lines running between the new electrical panel and the air-conditioning units.

So far, all three systems have heated and cooled flawlessly. The equipment seems to be sized correctly, with no short-cycling or struggling to meet set points. Our energy bills are reasonable for a house of this vintage, and best of all, we’re completely comfortable. The install was enormously expensive, a total pain the ass, and absolutely worth it. Despite the stress, I’m glad I was the one to introduce central air to the Ordinary House. With any luck, our new systems will keep us comfortable for several decades until the next wave of mechanical technology comes along. Whatever that may be, I just hope it requires smaller holes.

Anybody need five window units?

Pretty ordinary #006: Heated edition

Cue excitement.

If you’re not sure what’s pretty or exciting about this photo, welcome to the blog.

thermostat

After a week-and-a-half of heavy-handed intervention, William Reed’s Ordinary has officially joined the 21st century with modern, efficient heating and cooling systems. There are a few odds and ends for the HVAC contractor to finish up, and a county inspection to pass, but warm air is flowing from the floor vents as I write this. Stay tuned for a detailed recounting of how we integrated central air into a house that was built more than 150 years before it became commonplace…

Stairway to heaven-ly heat

Two major obstacles stood in the way of installing central heat and air in our house. The first, inadequate electrical service, was taken care of recently when we upgraded to 200 amps of power. A less costly, but no less vexing issue was the fact that our attic was only accessible from the top rung of a step ladder through a minuscule 18″ wide scuttle hole. Barely adequate for this scrawny dude to shimmy above the ceiling, it certainly wasn’t large enough for a furnace and full-size sheets of plywood to make it up there.

scuttle hole

(In case you’re starting to question our taste, I do realize that the color clashes in that photo are nothing short of horrific, and assure you that they are NOT intentional.)

An attic stair was the only solution to our ceiling access problems. Fortunately, finding a home for the sizable hole required for these was easy. In the sitting room at the top of the stairs was a unsightly set of metal louvers disguising an absolute beast of a whole-house fan in the attic.

louvers

This thing looks like it was pulled off the nose of a Beechcraft King Air 350i Turboprop.

attic fan

Unfortunately, we never used it because the knucklehead who wired it reversed polarities causing it to blow air down, holding the louvers in the ceiling closed, rather than sucking air out of the house as intended. For the record, whole-house fans aren’t well-suited for this climate. Our cool summer nights are typically accompanied by high humidity levels, so even though the fan might have lowered temperatures downstairs, it would have been sucking in sticky, uncomfortable air. Then as that air heated up throughout the day, you’d end up with a soupy, sweaty house. If you live in Flagstaff, Arizona or Portsmouth, Maine, though, a whole-house fan can be a lovely thing to have.

Our attic is actually fairly pleasant as far as attics go. It’s tall, has beautiful 2-1/2″ wide oak ceiling joists that make walking easy and old-school wood joinery that makes my heart go pitter-patter.  And this time of year it’s not Hades-hot.

Without belaboring the details, over the course of two days I managed to do the following:

  • disassemble and remove the whole-house fan (a huge thank you to my uncle Gregg for his assistance with this – his ingenuity seems limitless, and I would certainly have killed myself trying to do it alone)
  • slightly enlarge the existing hole for the attic stairs
  • install a wood header to frame the opening and support the stairs
  • install and adjust the stairs for a perfect fit

I haven’t had many opportunities to use my carpentry skills since moving to Hillsborough, so it was nice to see some sawdust flying again. There’s a fair amount of work left to be done to patch the portion of the hole not occupied by the stairs and to trim out the opening, but the stairs are functional which means that we’ll have a furnace up there this week or next.

finished stair

We paid a few extra bucks for a nice set of aluminum stairs with insulation and weatherstripping. The hope is that they’ll prove a bit more durable than standard wooden attic stairs and that they’ll help stem the tide of warm air that escapes through our ceilings each day.

The HVAC boys are in the house and we’re like a couple of kids on Christmas morning watching the install progress.  Until they’ve got us up and running for good, we’re much more comfortable thanks to our neighbor David, who kindly loaned us a large kerosene heater that puts our electric radiators to shame.

Amped up

Any novelty that accompanied the challenge of living through this winter without heat is long gone. I think it disappeared completely right around the third consecutive morning with temperatures in the teens early last week. Heating this house with electric radiators mid-winter is, to use an indelicate analogy, like pissin’ in the ocean: it just doesn’t make much of a difference. I’ve made peace with our modern-day frailty and look forward to the day when we can click the thermostat over to ‘heat’ and luxuriate in a living room with temps somewhere north of arctic.

Fortunately, that day is almost here. Our biggest obstacle to installation of the new HVAC systems was our undersized electrical service. The previous owners limped along with only 100 amps by using fuel-fired appliances: the boiler, water heater and dryer all run on natural gas. To complicate matters, the main electrical panel is almost full, limiting our ability to add new circuits in the future. And to top it off, our existing service entrance was outdated and recently blew itself apart, probably because the radiators were showing it more action that it had seen in years.

Last week our electrician got us upgraded to 200 amps, the de facto standard for electrical service in today’s energy-hungry homes. Before the switchover, the main electrical wire dropped from the street to the house, went down the masthead, punched into the crawlspace of the library and looped around to the meter box on the back side of the chimney. From there, a chunky metal conduit ran along the foundation across the back of the house to the main electric panel in the basement. This arrangement was roundabout, ugly, and lagged behind modern building codes.

old meter

In order to avoid the cost and disruption of completely rewiring the electrical panel in the basement, the electrician used a combination meter base and breaker box. This will give us the ability to pull new circuits directly from this box, rather than the maxed-out panel in the basement.. A chunky feeder cable runs from the meter/breaker box, through the crawlspace of the library, across the ceiling of the basement and into the existing panel. When Duke Energy moved their wires to the new service entrance, it took the electrician only about an hour to wire this cable into the old panel, restoring power to all our existing circuits.

new meter

I wouldn’t classify any electrical equipment as attractive, but our electrician did very neat work and his installation was tidy enough to elicit unsolicited praise from the county electrical inspector. Come spring, I’ll paint out the new box and masthead and remove the old meter base and conduit.

service entrance

Most of us could care less whether we’ve got 40 amps or 400 as long as the lights come on when a switch is flipped.  I’m happy to know that we’ve got a professionally-installed electrical service, but ecstatic to know that we’ve got what it takes to install central heat and air.  One week from today, a service van will pull into our driveway with the first furnace in tow, not a moment too soon.