The Lawrence Street House – Solar Electric [update]

[added revised pricing on solar hot water system and total cost; even better than I originally thought]

In addition to thinking about our landscape design, finishing the structural plans and selecting some of our finishes (more on those to come), we’ve been looking at our solar configuration(s).

Typically, you’ll do a 2 or 3 KW photovoltaic and a separate hot water system. This maximizes tax credits and utility incentives and generates a lot of electricity and hot water. Photovoltaic systems are still expensive and the cells are getting more efficient, but they’re still relatively inefficient. HOWEVER, they are still worth it in my book.
Hot water systems typically generate a lot of hot water for a relatively low cost. As a point of comparison, a 2 KW equivalent hot water system will cost about $8,000 to $9,000 where a 2 KW stand-alone pv will be in the $13,000 neighborhood. Both of those are before credits and incentives.
But our LEED rater, Eli, has a friend who is an engineering type who had a thought. This, of course can sometimes be dangerous (engineers having thoughts can be kind of like architects having an idea). But the more I’ve considered his thought, the more it makes sense to me.
What he observed is during the summer, a typical solar hot water system will heat a normal 120 gallon solar water tank up to maximum temperature, then shut off. Two “problems” with that. First, 120 gallons is more water than most people use (a typical home has a 52 gallon water heater). Second, when it shuts off, in the time of year when you get the most solar, you are basically throwing away that extra energy by not collecting it. Two very intriguing points.
So his thought is to bag the solar hot water system with its oversized tank, pumps, plumbing, etc and put that money into upsizing your photovoltaic system. So I got some preliminary pricing on upsized pv. A 2.1 KW system is about $13,500 ($1,200 net after credits), a 3.2 KW $20,000 ($4,500 net) and a 4.9 KW system $29,400 ($9,500 net). A hot water system nets out at about $4,200 after credits. So a 3 KW plus hot water system nets at about $8,700 but boosting it up to almost 5 KW (3 KW plus the 2 KW hot water) nets at $9,500. And, during the summer, we can sell the extra back to our utility and build a credit for the winter.
We’re strongly leaning toward the 4.9 KW system. We’ll couple that with a small, 40 gallon high efficiency water heater (like the Rheem Marathon). I have Eli checking to see how much energy we should actually save (which is more important to us than the tax credits) and I’ll report how that pencils out.

The Lawrence Street House – Front Porch continued…

I know it’s been a while since my last post. There are a couple of reasons for that. First, I’ve been in the final stages of completing my Sustainable Building Advisor class and the last part of the class got even more intense. Second, we’ve been also finishing the working drawings so we can get bids and find out just where we’re at on our budget.

In this post, I want to kind of tag on to my Front Porch article previously in April. This has been a huge part of my wife and my personal culture shift and paradigm that it became a major part of our design. It is also a major part of our landscaping layout. Thankfully, our landscape architect, David Dougherty (Dougherty Landscape Architects), who designed our landscaping in our present house 11 years ago was called into service to design our new one. David understands our desires (our current landscaping is incredible), sustainability and front porch philosophy.
Because our house faces probably the major bike and pedestrian east-west connection through town, we wanted to have our house relate well to that. It’s interesting that our City code allows us, because we are on a corner lot, to pick one side as the “front” and the other one as the “side”. This means, if we wanted to, we could build a 6′ high, solid wood fence the entire 150 foot length of our lot along this wonderful ped/bike corridor. Real neighborly, huh?
Of course, that would be totally contrary to what we envision for this house. We want to be part of the neighborhood, not project this idea that “this is my space; stay out.” Yet, because we are on a major circulation path, we do want some level of privacy for our outdoor living space. From the street as well as from the secondary home. Therein lies the challenge.
And David met that challenge. The image above is a segment of our conceptual plan, showing the porch and the yard. You can download a full size plan by clicking here, but I want to focus my discussion today on just the front porch and the yard.
I’ll start with the yard first. As I said, we wanted some level of privacy when we’re out having a barbecue or family gathering. After all, this is a major circulation path. Not a wood fence or hedge of arborvitae. This isn’t a major path for cars. We were mowing our lot the other day and in a fifteen minute period or so, I counted 22 bikes, 6 pedestrians and 2 cars passing by. So sound privacy isn’t much of an issue. We also don’t want to be completely on display. David captured that essence wonderfully and we are now taking this conceptual plan to that next level with only minor changes. We are reducing the lawn size even more (that IS our only lawn area — about 250 sq ft on a 9,000 sq ft lot) and providing some more patio for our outdoor table, chairs and umbrella. I’ll go into more detail as this progresses in a later post.
If you’ve read my April post about front porches, you’ll understand why our front porch is the way it is; if you haven’t read it, do that now, then return to this spot. We are envisioning some stone insets between the porch steps and the sidewalk wrapping around the corner. This allows people to cut the corner walking from 15th to Lawrence (they will anyway, so why not go with it?) and makes a hugely-inviting “front” to our home. My wife and I can see ourselves sitting out on the front porch on a Saturday morning, greeting passersby and maybe even inviting them up for a cup of coffee or ice tea (if summer ever arrives…). Neighborhood is all about this interaction and that is some of what we’ve lost in our recent trends in house and subdivision design.
That’s probably enough information for anyone to process in one sitting. As I mentioned, I’ll talk in more detail about some of our other landscape ideas later.
But this parting thought: most people design a house, get everything done, sometimes even start construction, THEN think about colors, plants, patios, etc. It needs to happen sooner, in this earlier stage of design, so the indoors and outdoors have some cohesive connection (and so it fits into the budget). Good design is comprehensive.