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Mechanical » Our Sustainable Home
Browsing Topic: Mechanical

Plans partially into the city

August 13th, 2008

Unfortunately our Civil Engineer has become swamped with other projects and like many in his industry are just so busy with other things, don’t have much time for a small project like ours.

Since I couldn’t be sure when I’ll actually have the Grading & Drainage plan in my hands, I decided to take what I had down to city hall.

Unfortunately when I tried to hand in the revised drawings 4 of them were rejected because it had the wrong stamp. A set of plans can either have the architect’s seal with a space for them to sign by hand, or it can have the signature embedded as part of the seal. Mine had the former and since they had been sent electronically, weren’t signed.

I was able to submit the new Mechanical drawings (now showing the HRV lines).

I’ve now received the drawings from the architect with the digital signature, and will reprint and redeliver them to city hall in the next few days.

I should mention: when I had to get the plans printed I used Sure Print and Design. They are a little bit out of the way for me, but their pricing for 2’x3′ engineering-bond pages was significantly lower than anywhere else I found. (And they were really nice folks, too!)

Posted by Colin
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Simple Ventilation System

July 1st, 2008

One thing that I still think is missing from our plans is a very simple air movement system.

At the very first meeting with our architect we mused about how crazy it was that no homes seemed to incorporate the very simplest idea in home cooling: a fan that draws cool air from a basement and pushes it to the upper floors of the house. The fan could even be reversed in the winter to warm up the basement with air from the upper floors.

Somehow over the course of development this idea started to seem impracticle because of the efficiency of the mechanical systems, and a lack of space for the ductwork to run. I think there might also be some building code issues that require a balance of intake and output on each floor (which would defeat the purpose, to some degree).

If I find the time, I’d like to settle once and for all if this is a practical and feasible idea.

Posted by Colin
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Permit application short on two counts

June 9th, 2008

We received one call and one letter letting us know that our building permit application could not be approved until we:

  1. Submitted a Grading and Drainage Diagram with our build plans (a new requirement for all new construction in the city).
  2. Submitted revised mechanical drawings that show the location of the HRV ducting. (Because our heating system is entirely radiant flooring, one has to show how the ventilation will work.

We’ve asked the Mechanical Engineer to start work on the HRV ducting but we’re not sure who will provide the Grading diagram yet.

Even though it may seem like we have lots of time with our start date being moved back to August 1, we know all too well by now everything that can be rushed, should be rushed or it will never get done.

Posted by Colin
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Plans submitted to city!

May 29th, 2008

This day has been a long time coming: we’ve finally gotten a full set of plans into the city for final approval.

Our initial PAL Review in 2007 was for a stick-frame house with a proposed forced-air heating system. The final plans call for an ICF house with a radiant floor heating system. Several key structural members were also changed in the roof truss design.

While everything has been signed off on by the appropriate professional, we won’t know for certain that the plans are approvable for 10 days. I’m especially concerned about the Plumbing form which the clerk just accepted and said “the plumbing guy will figure it out.”

In addition to our concerns about approvability, we don’t yet have the final budget numbers from the various trades and sub-trades.

At this point we are tentatively looking for places to rent during construction, but probably shouldn’t sign any leases until we receive final approval from the city and finalize the all the significant budget numbers.

Posted by Colin
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Foolish patience

April 21st, 2008

You’d think by now I’d have learned. Unfortunately my foolish patience has wasted another few weeks while we waited for the Mechanical Engineering drawings.

There was some miscommunication about what was to happen next and somehow the radiant-floor guys didn’t know they were to proceed with providing the mechanical designs for the house. They’re “getting right on it.”

Posted by Colin
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Change of Mechanical Systems

April 4th, 2008

In another bold move akin to the change from stick-frame to ICF walls, we’re going to be changing from a forced-air system to radiant floors.

The bad news is, putting a radiant flooring system throughout the house costs about 4x that of a forced-air system. But we made the change because of its high efficiency, extreme comfort (according to several sources who raved about their radiant floors), and ability to easily take advantage of solar heating, when we’re ready.

It’s also the kind of thing you really want to invest in at the time of construction, not after the house (and floors) are already in place.

Speaking of floors, that was one item we quickly struck off our list when trying to figure out how to rebalance the budget. Instead we’ll just live with the concrete/gypcrete floors until our finances can tolerate a little more debt.

The system we selected includes the Triangle Tube Prestige Excellence Combi Boiler within a 14 gallon internal indirect tank to provide the household hot water.

Since the house is air tight, we’ll also be adding an HRV (Heat Reclamation Ventilator) with an electric coil to moderately heat the air as it comes in to avoid the feeling of drafts.

We’ve asked the flooring people to provide the Mechanical designs that will be required to obtain a building permit. The Mechanical design should cost around $900-1200 for our project.

Posted by Colin
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Follow-up: Properly sizing mechanical systems

November 22nd, 2006

Follow-up to: Book: The Natural House

Alex was just showing me an article called Smart and Cool ($) that appeared in a 2005 issue of Home Energy magazine.

In summary: Over-sized air conditioners aren’t just inefficient, they can make your house uncomfortable to live in. As I hypothesized about furnaces in the previous post: AC units cool and dehumidify more efficiently, the longer they run.

A heavy-duty AC unit will run in short bursts; not long enough to dehumidify at all because the water won’t have time to run off the cooling unit in the ventilation system. When the AC turns off, but the blower keeps going, the air picks up the small amount of water that had started to collect, and sends it back into the house making it uncomfortably humid.

In contrast, an AC unit that runs all the time eventually adds so much condensation to the cooling coils, that the water drips off and is drained away out of the ventilation system and therefore, out of the air.

When planning your mechanical systems it seems to me that it is actually worse to wind up with a heating or cooling system that is too strong than one that isn’t strong enough.

We aren’t planning to install AC at this point. We think we can keep the house cool by opening windows in the evening to collect cool air, and relying on good insulation and air circulation to keep the house cool through the day. In Toronto’s climate, we find there is only about 1 week every year where our current home (even as badly insulated as it is) is uncomfortably warm. In our new house, we’re hoping we find that to never be the case.

I think people would be amazed at how comfortable they could make their homes if they stopped relying on AC and simply opened their windows in the cool evenings, and sealed their house during the day. In our climate, residential AC really seems like an enormous waste for its limited benefit.

Posted by Colin
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Book: The Natural House, Daniel D. Chiras

November 21st, 2006

The Natural House, Daniel D. Chiras
ISBN: 1-890132-57-8

The first half of this book, while interesting, was dedicated to alternate forms of home construction (cob, rammed earth, straw bale, etc.) that aren’t of much use for our particular project; The city isn’t quite ready to have folks try out these methods in locales where their house can actually fall on another house.

But the second half is chock full of very practical suggestions to keep in mind when designing a house. One suggestion in particular came to mind yesterday, after our furnace received its winter maintenance visit.

“Don’t pay extra to give your heating contractor peace of mind.”

The technician indicated that our 26 year old furnace was putting out 90,000 BTU, whereas our small house probably needed 45,000 BTU “at the very most.”

According to the book (and as was apparently the case when our furnace was bought) most heating contractors will over estimate the amount of heating you need for your home. This happens, if not for the unscrupulous reason that they get to sell you a bigger furnace, because they don’t want your furnace to be unable to adequately heat your house.

But consider this: when have you ever encountered a house who’s furnace couldn’t heat the house? Indeed, it probably stayed off most of the time and came on from time to time to blast the temperature up a couple of degrees and then shut down again.

This can’t be more efficient than a system that runs steadily. To my thinking, a furnace which is the ‘right size’ for your house is one that has to run constantly on the coldest day of the year to keep your house at a comfortable temperature.

And what happens if you have an unusually cold run of weather for your region? It’s not as if the furnace, unable to maintain 22°C will drop to 0°C. If it can’t keep up, it might become 19°C and you’ll have to put on a sweater, or run an electric space heater when and where you need it.

Obviously electric heat is expensive, but just think how much is wasted by running an over-sized furnace every winter, compared with running an electric heater for a few hours on a couple record-breaking cold days in a rare extra-cold year?

But I think I’ve digressed…

The Natural House also covers topics on insulation, window technologies, flooring, non-toxic paints, solar electricity, solar water heating, and much more. It’s a great read for anyone trying to get to the crux of what they need to know about the materials that go into their home.

Follow-up: Properly sizing mechanical systems

Posted by Colin
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