Metal Roof

Tommy and Bryce braved the heat recently to put on our galvalume metal roof. We only get to do this a few times a year, so it’s always satisfying to be up in the air, above the trees while bending and crimping metal.

We used the 26 gauge Advantage Lok roofing pan by Union Corrugating, which we get from Better Living. This mimics the look of a true standing seam, but it actually snaps and locks on the previous piece rather than getting field hemmed together. I would love to be putting on a true standing seam, but I have yet to find anybody that will sell me the pans. (Most roofing companies in town make their own pans and are generally interested only in making pans for jobs that they are going to install). Still, the Advantage Lok pans meet Miami Dade County’s rigid code for uplift in a hurricane zone, and we still get the fun of field hemming the eaves and rake of all pans.

I get all of my eave, rake drip edge, two-part non-exposed fastener ridge vent, and metal plumbing vent boots bent at Martin Roofing in town. I could get a lot of this from Union Corrugating, but since the trim detail is a bit more specific and complicated, I prefer to get it local in case I run short or have an issue. Plus, it’s a lot of fun to go into Martin Roofing’s shop and work with Neil on figuring everything out.

The big change for us on this roof is that we are actually not doing a conditioned attic like we have usually been doing, but are going the route of the more traditional vented attic (with soffit and ridge vents). We started going with the conditioned attic space and spraying the underside of the roof deck with open cell foam as we were running duct work up in that space and it’s obviously not efficient to run cool air conditioned air in a hot attic. For this house, we went with the traditional vented attic for two reasons:

1) We have no HVAC in the attic

2) Going with a 6/12 gable roof is a lot more roof area than the simple 3/12 shed roofs that we have doing, so it would take a lot more insulation on the underside of the sheathing. Plus, our Passive House modeling calls for R60 insulation in the ceiling, which is just prohibitively expensive for us in spray foam. But, achieving this with blown cellulose (recycled newspaper) is very affordable. Plus, since we already ran a plywood taped air barrier on the 2nd floor ceiling, we don’t need the air sealing qualities that spray foam would provide.

We also made sure to put all of our plumbing vents on the north side of the gable roof as Joey has been diligently investigating the possibility of a solar thermal hot-water system and/or a grid tied photo-voltaic system. Stay tuned…

Project: 6th Street SW · Tags: , , , · 1 Comment

Exterior Doors…

Tom has been busy this last day or so both manhandling and finessing our extra deep exterior doors into place. While we went with the Serious 525 fiberglass series for the windows, we just couldn’t justify the extra cost for the Serious doors. Plus, all Serious is doing is buying prehung doors by Thermatru and slipping their own glass into them, so it’s still a conventional frame.

Instead, we opted to buy Thermatru Smooth-Star fiberglass doors with just double pane low-e glass in them. To meet the Passive House Standards with the higher U-value door glass, our modeling called for increasing our exterior wall insulation from ten to eleven inches. Just that extra inch of insulation is still a few thousand dollars cheaper than the cost of the triple-pane Serious glass in a standard Thermatru door.

A few wrinkles: We were able to get Thermatru to make a 12″ thick jamb, such that our doors hinge on the interior side of our double stud and are able to swing freely. However, the deepest sill we could get was only 8″ deep. So, if you look at the photos, you can see the jambs of the doors stick past the actual sill by a couple inches.

To solve this flashing issue, we had Martin roofing solder up some copper door pans for our doors to sit in. It is probably overkill, but we also ran rubber and caulk below our copper door pan as well. Also, before seating the door in the pan, we adhered a thick self stick rubber membrane to the bottom of the aluminum sill such that it wouldn’t be in contact with the copper, which could potentially react and corrode the aluminum.

As far as aesthetics, Joey went with a 3/4 lite for our two front doors to try and have a little bit of a unique look.

Project: 6th Street SW · Tags: , , , · 1 Comment

Double Stud walls

Now that we are under roof, we’ve been concentrating on our interior framing.  First up was building the interior half of the double stud wall around the outside of the house.  It moved pretty fast except for continually having to shuffle things around to have room to build the walls.

Originally, our Passive House calculations called for a 3″ insulation gap between the two walls; however, that was with the triple pane Serious 525 doors.  Unfortunately, we found the doors to be not financially viable, so are instead using double pane Therma-Tru doors with triple point locking on all doors (more on this later).  To compensate for the slight loss in performance, we had to bump our separation to 4″, making the walls 11″ thick now.

As far as building them, it’s just a matter of copying the layout for the exterior wall.  We were able to add a little bit of value framing by not having to worry about exterior sheathing having to break every four feet and left out studs whenever a window was within two feet of that four foot layout.

These are definitely the straightest walls we’ve ever had as string-lining exterior walls still has a small amount of imprecision. In this case, we were able to chalk a straight line on the underside of the trusses all the way down and went ahead and attached the cap plate to this prior to lifting the wall up.

We can’t wait to get the windows installed and then jamb them out to really get a sense of the depth of the walls.

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Attic air sealing detail

We are trying a new attic insulation and air sealing detail on this house. We have been a big believer in conditioning the attic space in all of our houses and have been spraying open cell foam on the underside of the roof sheathing down to the top plate. Typically, we have been running the duct work for the 2nd floor in this attic space, so it makes sense that it is terribly inefficient to run duct work that is delivering cool air in a hot attic space. Also, because we mostly use low slope shed roofs, the volume of the attic is not generally that much of a space to condition.

For the Passive House standard, we need to achieve a ceiling R-value of 60. To do this in foam is just too expensive for us (more surface to cover with a gable vs shed roof), so we find ourselves returning to dry blown cellulose, which you see in most houses. Traditionally, the big downside for cellulose is that it won’t prevent air infiltration. The system of just blowing the cellulose over the ceiling drywall leaves potential areas of air leakage around lights, through drywall cracks and around the inside edge of the top plate. This was not going to work for us.

To get a great air barrier, we actually nailed up 1/2″ plywood to the underside of the trusses. Before even setting the trusses, we made sure to put down a small 6″ ripper of plywood on top of the cap plate of the wall and taped that outside corner of the plywood to the exterior sheathing really well. Once the trusses were set, we continued this plane of plywood all the way across the ceiling and taped all the seams.  We made sure this ripper of plywood projected past the interior side of the wall to have enough room to tape the seam.

We did have to notch into the plywood to attach the hurricane clips. We did our best to tape those notches, but I think I’m going to have to use a little foam there to seal the deal.

We are going with all sconces for lighting and will also put the smoke detectors on the wall, so we don’t have to worry about any penetrations of the plywood. If we were to have ceiling lighting, we would have to fir down a chase on the underside of the plywood. John Semmelhack had an interesting idea if we had to go this route of actually building a mini floor system on top of the wall plates of 2x4s or 2x6s and plywood. This would be installed before setting trusses too and the tape would have to be installed on the sky side of the plywood instead of the underside. Besides giving a chase in the conditioned space to run recessed lighting or duct work, this would create a platform to set trusses on, which ups the safety and ease of installation for truss setting.

As far as costs, I really don’t think there is much of a cost increase from this method. Because cellulose is so much cheaper than foam, the insulation cost savings makes up for the cost of the material and labor of installing the plywood. It’s a slightly different story if we were to build a false floor system though, as the labor and material costs from that would be moderately significant.

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Rheem Heat Pump Hot Water Heater

Riverbluff is the third house where we have used the Rheem Heat Pump Hot Water Heater, as we have been really happy with the results.  Rheem air-source heat pump water heaters work much like a refrigerator in reverse. The heat pump extracts the heat from warm air, intensifies the heat with a compressor, delivers the heat to the water, and exhausts the cooler air. Because it uses the warm ambient air temperature to do most of the work, it is a very efficient way to heat water.

Our greatest attraction to this type of hot water heater is the energy savings.  The estimated annual electric cost for this unit is $234.  The operating cost for most 50 gallon electric water heaters is around $500 or so.  The Rheem Heat Pump Hot Water Heater is costing us about $1600 versus $400-500 for a standard electric.  So, it’s a pretty quick payback of about 4 years.

Realistically, energy efficiency features are still not the major selling point of our spec houses, so I don’t think I’m realizing this extra cost. Or, sadly, I think I could just put a normal hot water heater in and the house would still sell for the same price.  (As an aside, Joey has started to do some research into mortgages that take into account energy upgrades that will lead to a higher monthly payment, but will be made up by lower utilities bills.  Unfortunately, I don’t think the mortgage industry has gotten completely onboard with that.)  Anyway, there is a little bit of a silver lining for us.  This hot water heater, along with a few other features we put into our house, get us to a low enough HERS rating to qualify for a $2000 federal tax credit. The tax credit is for contractors who build new homes that are at least 50% more efficient than a 2004 code built house. This tax credit honestly has helped us adopt certain features as the norm, like an ERV system and the water heater.

Why not gas? Part of it is the extra installation cost of running the gas lines and hooking up a gas unit.  We’re building an all electric house, as we have been really happy with the efficiencies of our ducted heat pump systems and have also switched over to an induction cooktop for the kitchen.  So, it’s hard to justify running gas for just one appliance. Plus, by going all electric, it opens up the possibility of the house being completely supplied by renewable resources in the future when P.V.s become more affordable.

I do acknowledge that the gas tankless has certain advantages, namely the lifespan of a tankless is quite a bit longer than a tank heater.  Plus, as far as energy usage, if you’re a purist, a lot of energy is lost traveling down the electric lines from the power plant to the house. So, if you were to factor in line loss, a gas tankless should be more efficient. At this point, for the small residential scale that we are building at, I don’t think solar hot water makes sense simply because it’s such a long payback time versus the heat pump hot water heater because of the much higher installation cost.

One thing to be aware of is that they are noisy, which we learned the hard way.  We put our first one in on the second floor of the Mulberry house thinking it would be most efficient to be as close to the bathrooms as possible.  Because they are a heat pump, there is fairly audible constant hum to it, which is a little obnoxious. By building high enough crawlspaces, we’ve taken care of the sound issue. Plus, we get the added bonus of the hot water dehumidifying the basement by drawing in warm, ambient air and spitting out cool, dry air.

Special thanks to Eleanor for hopping down to the crawl space to model the Rheem unit.  I mean, wouldn’t you rather look at a cute baby than a boring hot water heater?

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Tax Credit for Home Upgrades

Just announced…note that this is not for new construction, just existing buildings.

Greetings from the Virginia Department of Mines, Minerals and Energy

Lieutenant Governor Bill Bolling announced that approximately $6.5 million is available for a second round of the Virginia Energy Efficiency Rebate Program to make homes and businesses more energy efficient. Energy efficiency improvements include upgrading heating and air conditioning equipment, adding insulation, replacing leaky windows, and other improvements that reduce energy consumption and utility costs. Homeowners are eligible for rebates for 20 percent of the costs of qualifying energy conserving products and services, up to $2,000. Commercial consumers are eligible for 20 percent of their costs, up to $4,000. Qualified home and business owners also can reserve an additional $250 for a certified energy audit.

Three appliances have been added to the program for the second round; refrigerators, dishwashers and clothes washers. The online application, rules, forms and additional information are available at

Applicants can apply to reserve funding for a rebate. Once approved, they then have up to six months to complete the work and redeem the reservation for a rebate check. Applications for rebate reservations will be processed in the order they are received. Once reservations deplete available funds, applications will be placed on a wait list in the order received. Wait-listed applicants may be approved for rebate reservations if additional funds become available. (The first round of funding for efficiency rebates totaling about $10 million was sold out in less than three weeks when the program opened in late October.)

The Virginia Energy Efficiency Rebate Program is administered by the Department of Mines, Minerals and Energy, using funds from the American Recovery and Reinvestment Act. More information is available at

You received this email because you signed up to be notified when a second round of efficiency rebates was available. Do not reply to this email. If you have a question please send it to

A separate Solar and Wind Incentive Program also has opened a $3.5 million second round of funding to help defray the costs of solar electric, solar thermal and small wind energy systems for residents, businesses, and non-profits. Information is available at

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Smart Grid in Charlottesville

I’m a bit behind the news, but after seeing a presentation recently by a Dominion Power representative, I went and looked up what our sole electricity provider is doing for the environment. I’m excited to report that they have begun a pilot program in Charlottesville to install smart meters with the goal of creating a whole smart grid for improved electricity monitoring. I think this is a sign of the future. Our current electrical grid system is basically the same technology we had 100 years ago! It’s time that we had the ability to better gauge consumption use. One of the key advantages of smart metering is the ability to charge variable rates at different times of the day. By implementing variable rates, people can start to track energy use based on excess load times. For example, run appliances (dishwasher, dryer) at night when loads are low.

Net Metering
If you happen to generate electricity from your own home, you can put that extra energy back on the grid for others to use. With a smart grid in place, I think Dominion should encourage this technology as a means for reducing loads on the grid. For this to happen, we will need lower-cost and improved PV and wind systems. Current incentives (see other post) are currently helping get more energy onto the grid. Latitude 38 has not yet purchased renewable energy systems for our homes. Given the relatively smaller size of our houses (~2000 SF), we have found money is better spent on high efficiency heat pumps, tight ducts, proper blown insulation and insulated windows. Solar water heaters appear to be the most cost competitive of these renewable energy sources and we are considering the payback of these systems.

Dominion VA Green Power
If you are still net negative energy, you can still support renewable energy by signing up for renewable energy through Dominion. You have to pay $.015 extra per kW. For a usage of 1000 kW/month, it would be a $15.00 increase. The request does not mean that energy will go direct to your house from a renewable source. The amount you need supplied is purchased in RECs (Renewable Energy Credits). In Virginia, we must purchase RECs from other geographic areas, rather than put renewable energy directly onto the grid, as we do not have many sources of renewable energy in close proximity.

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Energy Efficient Mortgages

Energy Efficient Mortgages (EEMs) are a new development in financing affecting homeowners purchasing new construction and upgrading existing homes. Banks are starting to recognize the additional value that energy efficient building techniques bring to long-term home value. With a licensed contractor doing the work and a 3rd party tester verifying the HERS Index rating of the home and providing a report showing estimated energy savings, a lender can either add the potential energy savings onto the homeowner’s income and/or add the energy upgrades to the value of the home (dollar for dollar) to improve the Loan-to-Value ratios.

For more information, contact your mortgage lender or contact a lender listed on the Energy Star site. This link says that EEMs currently are recognized by FHA lenders and those that sells their loans to Fannie Mae or Freddie Mac.

Another key element in getting energy efficient upgrades included in a home’s value, even without an EEM from the lender, is the recognition by appraisers of the increased value of the home through reduced operating costs, reduced maintenance costs, and increased quality of life in a properly commissioned home. I am not very familiar with how appraisers in Central Virginia currently value energy efficient building techniques. If you look at a Uniform Residential Appraisal Report, you will see in the Sales Comparison Approach a line called “Energy Efficient Items.” Many appraisers will just put “Standard” or “Average” for homes, even though there is not a clearly recognized standard. As more and more people have their homes scored with a HERS Index rating, the comps could become more relevant in this category. Because appraisers are data driven, it appears as though the HERS rating should be recognized by the appraisal industry, as it is in most green building performance certification programs. If you are going to have a home appraised, talk to your lender about EEMs and the appraisal process to see if you can have energy efficient features included in the value of the home.

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Energy Efficiency – Incentives for Homeowners

The City of Charlottesville, the Commonwealth of VA, and the federal government are all providing incentives to homeowners to make their homes more energy efficient. If you have (or have not) ever thought of improving the energy efficiency of a home that you already own, it may be worth your time to look at the paybacks of these incentives. I have tried to compile everything I know of here. If you know of anything I am missing, please let me know!


Property Tax Assessment for Energy Efficient Buildings
Scroll to bottom of City webpage for attachments
This is a creative incentive that gives homeowner’s a one-time 50% property tax credit if they are able to show the house is a 30% energy efficiency improvement over the building code standard. This can be certified if the house meets performance standards of the Green Globes Green Building Rating System, the Leadership in Energy and Environmental Design (LEED) System or the EarthCraft House Program; or qualifies as an Energy Star home under federal Energy Star criteria. There are a few certified Home Energy Raters in the Charlottesville area that can help.

Hot Water Heater and Programmable Thermostat Rebates

Local Energy Alliance Program
The City and County worked together to win a $500,000 grant for their proposal to create a local energy program designed “to achieve unprecedented energy and water savings by retrofitting buildings and installing renewable technologies in all end use sectors. The program is designed to achieve 30% – 50% market penetration and a 20% – 40% efficiency gain in 5-7 years.” This seems pretty ambitious to me, but I support their efforts. The program should be up and running in January, so I’ll post more info on this program as it becomes available.

A Green City (City of Charlottesville Incentives for Reference)
Spark (City of Charlottesville Incentives for Reference)


Efficiency Rebate and Solar and Wind Incentive Programs
New applications to the Efficiency Rebate and Solar and Wind Incentive Programs closed on November 18. Current requests to reserve rebates have exhausted the first round of funds. A second round of rebate funds is expected to be made available at a later date to be determined.

Dominion Power Proposed Programs
Dominion seeks state approval of 12 energy-saving and demand-reducing programs. These should be approved (or denied) in February 2010. Look out for info in your bill.

DSIRE (State Incentives for Reference)


Federal Tax Credits for Energy Efficiency (Energy Star)
Tax credits are available at 30% of the cost, up to $1,500, in 2009 & 2010 (for existing homes only) for:

    Windows and Doors
    Roofs (Metal and Asphalt)
    Water Heaters (non-solar)
    Biomass Stoves

Tax credits are available at 30% of the cost, with no upper limit through 2016 (for existing homes & new construction) for:

    Geothermal Heat Pumps
    Solar Panels
    Solar Water Heaters
    Small Wind Energy Systems
    Fuel Cells

Department of Energy (Federal Incentives for Reference)

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Home Purchase Tax Credits Extended

Federal Housing Tax Credit Extended

    $8,000 first-time home buyer tax credit
    $6,500 tax credit for repeat home buyers

If you would like to own a home, now is a great time to take advantage of federal dollars to help you out. To qualify for the tax credit, a home purchase must occur on or after January 1, 2009 and on or before April 30, 2010. Note also that there are income restrictions.

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