n05 Century Home Almost Net Zero

We will tour you through our home and explain the extensive remodel including energy upgrades and insulation. We will show you the 2 solar electric systems, including one on the garage which includes a battery back up system that would keep critical circuits in our home powered in the case of a blackout. Our 27 year old Thermomax solar hot water system is a site to see, producing 70% of our domestic hot water annually.  Located on the south wall of the house you will also see our 16 water rain barrel recovery system.

We are also happy to share how we restored the original Arts and Crafts beauty, using almost all reclaimed and second hand materials. We also want to show you our 1997 Solectric 4 door, an electric car built with a Geo Metro body and our Nissan LEAF.

Urban Sustainability Journey to Net Zero Century Old Home

by Pamela Burton and Jeremy Smithson

We are continuing to improve our 1908 Seattle house to conserve & produce energy with the ultimate goal of net zero.

Remodel goals:

• To decrease the energy needs of this all electric home while increasing the size of livable space.
• To restore the original architectural features.

Background: This home was remodeled a number of times over the years. The front porch was enclosed, roof overhangs were removed, large aluminum windows were added, all the original trim was removed, ceilings were lowered and the basement was finished.  Oil furnace was replaced with an electric furnace.

Baker Ave Before Construction – front view	Baker Ave After Construction – garage view

Steps taken:

The north side of the home lacked adequate foundation. This was the area targeted to add square footage to the master bedroom and a new entry hall and the re-creation of the original front porch. A new foundation was poured and the north side of the house was extended. The walls were built to include insulation with an R value of 40 and the ceiling, R-60. The existing hip roof was converted to a gable roof to make room for PV and the overhangs were replaced.  The pony walls of the basement were reframed and retrofitted for seismic resistance.  Every piece of lumber and trim we used was reclaimed or salvaged except for the OSB wall sheathing and some sidewall shingles.

Insulation:

A unique method of insulation was used with the installation of Polyiso foam board on the interior of all the exterior 2X4 insulated walls. This brought up the insulation factor to R-34.  Attic insulation was raised to R-57 with the installation of additional cellulose.  The basement walls were increased to R-33 with two layers of reclaimed R-13 batts in addition to the existing R-7.

Air Infiltration:

In 2009 we had a blower door test done and discovered that there was more leakage than we had thought – 2,150 CFM/50.  That summer we closed up the most egregious holes and retested at 1,950 CFM/50.  In 2010 we did more air sealing (3 cans of foam and 12 tubes of caulk) and retested at 1,450 CFM/50.  In 2011 we had our own retrofit crew come in and air-seal the attic and rim joists, and retested at 1,200 CFM/50.  Now the house is tight enough to need a heat recovery ventilator.

Windows:

Reclaimed low-E, Argon-filled vinyl windows were installed throughout the house. Thanks to an abundant supply of second hand vinyl windows at building material recycling houses the cost of window replacement was minimized and we were glad not to contribute to the new vinyl market. The negative response to the look of vinyl was conquered with the installation of very beefy reclaimed window casings and trim.

For those who may think that you can insulate too much, think again.  The insulation and window upgrade cut the heat loss of our home by 67%.  The heating season got shorter by more than a month, going from 7 to 5 ½ months. The design day heat loss of the home is 13,000 btu/hr.  It is much quieter inside now, and during the summer we can use night flushing to cool the home for most of the day.  How long to recoup the cost?  Who the hell cares, the house is nearly 100 years old!  We are not just building for ourselves; are you?  If this house lasts another 100 years, then we have made a nice contribution to posterity.

Home’s heat:

The home is blessed with extensive south and west facing windows that provide day lighting on all but the most cloudy days and 25% of the home’s heat. We removed the forced air system and added radiant heat in the basement ceiling, along with a programmable thermostat. We doubled the amount of PEX tubing so that heat radiates up and down. In the bedroom where we didn’t’ want to heat the space below we put the tubing in the wall.  In the bathrooms and kitchen we installed reclaimed cast iron radiators.  The heat source is a Solaraide 80 gallon tank with a single 4,500 watt heating element.  Future additional solar collectors will contribute some additional solar heat, perhaps 5%.  In the future we would like to replace this with an air-to-water heat pump.

Solar systems:

We began with a batch solar hot water system seated in a south facing nook. The reduction in the electric bill was enough to pay off the solar heater in 18 months.

We were so excited by the reduction in our electric bill that we next looked into more sophisticated solar hot water systems and located a used Thermomax hot water collector. We installed (30) tubes and a 60 gallon heat exchanger tank in 2003.

A 6.2 kW net metered system, made up of (33) Sanyo 190 watt panels and two Xantrex inverters was added in the fall of 2005. The annual production is 5900 kWh. Some trees and a hill to the east are limiting the potential PV production by about 900 kWh. In August 2008 we added another 2 kW to the garage roof. This has a battery back up system that will allow us to continue to power the house if the grid goes down.  This year we replaced those with made-in-Washington panels and placed them for better production.

Other measures taken:

• Replacement of 42 light bulbs with CFLs and LEDs
• Replacement of washer and dryer with a single unit that does both without venting.
• Use of power strips to disconnect electronics when not in use.
• Addtion of a home-made drain water heat recovery system for the shower.
• Replacement of the refrigerator with a more efficient model.

The landscape has been changed from lawn and junipers to drought tolerant and vegetable plantings. Rainwater is gathered in (24) 55 gallon recycled food waste drums that are integrated with rain-gutter system and then used in the garden.

In the spring of 2006 we purchased a 1997 Solectria Force electric car on ebay.  The car gets 3.3 miles/kWh going to the battery charger and has a 30 mile range.  It will go 65 mph on the freeway with four people in it.  1,000 watts of PV will run this car for 3,600 miles per year.  If gasoline is $3/gal. the electricity used for the car is worth $0.30/kWh. In 2011 we purchased a Nissan Leaf.

Results:

Total annual home energy usage prior to the work was 19,000 kWh.  This was reduced to 8,900 in 2005, and further reduced to 2,700 in 2006, or only 14% of the original load!  The car has added a few hundred kWh to this, so far.

How to get rid of that pesky 14%:

• Insulated window shades
• More Thermomax collectors
• Heat pump water heater for radiant system.

We are convinced that electric cars are a perfect compliment to PV systems anywhere.  Why?  Consider this:

An internal combustion engine is 15% efficient at best, including idling.  To get the fuel to the car requires the expenditure of lots more energy.  According to the U.S. Department of Energy, for every one unit of energy available at the fuel pump, 1.23 units of fossil energy are used to produce gasoline.  This means that you are getting just 16% of the energy that began its journey to your car as oil, and for every pound of pollution that it produces, probably more than a pound has already been produced.  This doesn’t include all the energy expended by the DOD and the defense industries.

Contrast that with the electricity coming from a PV array.  It goes through an inverter  & wires where it loses maybe 10%, then to the car’s battery where it loses another 20%, and then to the electric motor.  In our case our 31 kW motor is about 91% efficient, so we are getting about 66% of the energy that began its journey to our car as PV electricity.  No armies required.  Furthermore, we can get all the energy we need for the car from our rooftop in Seattle!

Where To Go From Here?

We can probably best increase the effect of improving our home by using it as an example to convince others to try some of these things in their homes, and that is what we hope we are doing here today.