360 Winnett » eco

Drain Water Heat Recovery

jeremybell — Sun, 31 Aug 2008 17:14:47 +0000

I’d read very little about drain water heat recovery (DWHR) systems prior to this weekend, but after seeing it referenced in some Energy Star documentation I decided to look into a little further.

Put simply, a DWHR unit captures heat from your waste drain water and redirects it back into system. It’s estimated that it can recycle up to 60% of the wasted heat, save up to 40% on water heating costs, and reduce your home’s overall energy consumption by 5-10%. It would be entirely cliched to say it’s saving money from going down the drain, but that’s more or less what it’s doing.

The technology is actually quite simple, and I must admit that I’m surprised it’s not mandated on all new home construction. A portion of the main-stack drainpipe is removed and replaced with the DWHR unit. The unit itself is simply a large copper drainpipe wrapped with a series of smaller copper tubes. The smaller tubes are connected to the cold-water supply, and the water running through them will see a temperature increase of up to 14°. This decreases fuel consumption simply because it requires less energy to heat the warmer water. Similarly, it works incredibly well with tankless hot water systems, which are known to perform poorly when the groundwater is overly cold.

I don’t believe there are many drawbacks with such a setup, although I’ve read claims that water pressure will drop once the device is installed. Apparently the “second generation” units present no noticeable drop in pressure, and I doubt they’ll have an affect on the PEX manifold system we’re considering.

From what I can gather, there are 3 different models available in Canada:

LC-GFX [from GFXTechnology]
The systems all look more or less the same, although there are a few key differences. The Power-Pipe appears to have more transfer tubes running in parallel, which I believe helps maintain pressure. The LC-GFX site actually scares me a little, and I couldn’t help but notice the conspiracy propaganda that litters it (stolen trade secrets, Energy Star hoaxes, and fraudulent tests?!). That said, it is significantly cheaper… although one has to wonder why (I picture an angry old man, bitter at the world, building these things in his basement).

Prices seems to range from $400 – $1200+, but they qualify for up to $260 in government rebates. To qualify for a rebates, the DWHR unit must be at least 30% efficient (43% for the maximum rebate), and to qualify for the Energy Star certification, it must be a minimum 48” in length.

Shades of Green

jeremybell — Fri, 27 Jun 2008 22:43:42 +0000

To date, the number one question, comment and critique of this project has been about our “green” commitment. Are we really being “eco-friendly”, or is this all just a vanity project? I suppose one wouldn’t put this all online if there wasn’t a hint of narcissism involved, but I like to believe I’m a little more humble than that. Regardless, I welcome all of the comments and I hope the criticism keeps us honest.

So what are our green strategies? As I’ve mentioned before, we hadn’t originally set out to build a green home. We simply wanted a larger home, and while this remains true, our priorities have changed along the way. We’ve come to realize we should be building a smarter home and not just a bigger home. We’ve also come to appreciate our eco responsibilities and felt it was important to document the realities that came with this decision. And there are realities that come with those decisions. Financial realities. We’ve evaluated a variety of eco-friendly solutions-~~and I’d love to use all of them~~-but we simply cannot afford to.

Many of the specifics are still in the air and won’t be finalized until we’re well into construction, but I thought I’d take this opportunity to shed some light on what green features we’re planning for:

Energy Star certification
Compact house footprint that fell below allowable coverage
ICF foundation
Closed cell, medium density spray foam insulation
Low E II insulated, argon-filled windows
High efficiency furnace + heat pump + HRV
On-demand hot water
Passive heating & cooling (solar chimney + cross ventilation + window shading)
Daylighting (clerestory + internal windows)
Energy Star appliances
Rainwater collection

CFL and/or LED lighting
Similarly, we’ve also had to abandon a variety of other green solutions as a result of their costs:
Green roof
SIPs
Geothermal heating & cooling
Grey water collection (although we haven’t completely ruled this out…)

Solar & wind power
I plan on discussing each of these topics in greater detail as we progress through the project, and I’m sure things will evolve as we continue to evaluate our options.

I’m assuming we will continue to face accusations of greenwashing, but hopefully this clears a few things up and illustrates that we are indeed trying to build the greenest home we can. Even if that shade of green isn’t as bright as we’d like.

How Green is Green?

jeremybell — Tue, 03 Jun 2008 03:07:57 +0000

What exactly spurs someone to take on a project like this? After 5 years in a small pre-war bungalow, my wife and I decided we wanted more room to start a family. So for us, this project was born out of a need for more space.

However, at some point along the way, our priorities changed. We still need the extra space, but I came to realize we could build a better home instead of a bigger home.

I’m sure “better” means something different to everyone, and for us it originally meant a modern esthetic with nice fixtures. And while we still want this, I’ve also come to appreciate how sustainability must work into the equation. So I’m left wondering… how green is green?

I’m not sure I have a definitive answer for this, but we are trying to do as much as possible given our budget. I’ve heard many claims that “green” doesn’t necessarily equate “expensive”, and while this is true in some cases, it’s hard to argue when you look at the budget. The fact is, we could have built a much larger home if we wanted, but instead we reduced the footprint so we could build it greener. I’m not suggesting it’ll be the poster-child for LEED construction, but it’ll definitely be better than it would have been.

I’m planning on discussing these more in future posts, but here a few things we’ve considered with the design of the house:

Window shading
Passive lighting
Passive heating & cooling
Rainwater collection
ICF / SIP construction

Spray foam insulation
Beyond the products & practices we’re considering, I’m often asked about the existing house. Why did we decided to bulldoze it? Why not build on the existing foundation? If we are going to demolish it, what will happen to the waste?

These are all excellent questions, and I must admit I hadn’t actually considered all of them. We had originally intended to build on our existing foundation, however proximity to our neighbors made this problematic. And I would love to recycle/reuse everything… I just don’t think that’ll be entirely possible.

Crushing and reusing the foundation is an intriguing possibility given our flat roof (we’re investigating covering it with crushed gravel). As for the rest of the house, we’re going to be selling/giving away as much of it as possible (the kitchen cabinets, radiators, boiler, etc). However, I realize that won’t make much of an impact and I assume most of it will end up in a landfill.

Not exactly the most eco-friendly solution, but that’s where we stand today. I hadn’t considered recycling the rest, but it’s something I’m definitely going to look into it now.

So these may not all be the greenest of steps, but hopefully they’re steps in the right direction.

Photo via Flickr user CasualTea

Prefab Considerations

jeremybell — Mon, 02 Jun 2008 03:13:26 +0000

My first instinct was to investigate a prefab solution when we began this project. I find the concept of prefabricated eco-modern homes very attractive, but living in Toronto definitely limited our options… apparently there aren’t many nearby factories. Who knew? I was particularly fond of Michelle Kaufmann’s Sidebreeze, but the shipping costs definitely made it cost prohibitive. Royal Homes apparently has a factory nearby that builds modern homes, however none of them would fit on our lot. Sigh.

Regardless of my situation, it’s great to see that Michelle Kaufmann is finally getting some attention with her eco-friendly prefab homes. More people should be paying attention…

Even if you’re not interested in going prefab, you can’t ignore her environmental message.