Archive for August, 2009
Using solar energy in any form in your house contributes in many ways to preserving and bettering the environment, and also the quality of indoor air and the home itself. With the way the environment is going down and fossil fuel prices are going up, energy efficient homes are the only kind of homes that can sustain in the 21st century and beyond.
Therefore, be it solar water heaters, lamps or an entire solar electric system – solar energy is an important step and consideration in making your home energy efficient.
Often though, creating a completely energy efficient requires extensive remodeling, in order to take care of heating, cooling, lighting, plumbing, insulation, electrical appliances and other things. This may not be feasible for everyone, and sure enough, isn’t, for many of our customers. Therefore we generally suggest homeowners who want to shift to an energy efficient to start by just adding solar panels, and a simple solar electric system. This takes a lot of burden off the environment and also your own budget in a threefold manner:
1. You are no longer using electricity produced fossil fuels to power your home (which is not very energy efficient either)
2. Although your home is still inefficient when it comes to energy, at least you’re using clean, renewable and home-made energy to power it.
3. You’re taking some measures to introduce energy efficiency without burning a hole in your pocket.
With a solar water heater, the cost is concentrated around the operational costs rather than the fixed cost. While picking a heater, it is a good idea to go figure how much it will cost you to operate each and then compare and pick the best one. The US Dept. of Energy gives you a formula to do this:
365 × 41,045/SEF × Fuel Cost (Btu) = estimated annual cost of operation
Where SEF is Solar Energy Factor – provided by the manufacturer of the heater and fuel cost is the cost of the fuel used to run the auxiliary tank – provided by your local utility provider. The fuel cost could be in British thermal units (Btu) or therms. Once you have this answer, you can compare it with other heating methods and solar heaters.
Installation of the solar water heater will be undertaken by the provider. As with the PV system, you need to ensure that your provider is experienced in installing the type of system you need and is licensed to do so. Since solar water heaters take up some space in and around the house, you will need to check with local building authorities, community laws and also state laws. Your provider should be easily able to install a system that meets all these requirements.
Maintenance of a solar water heater is very important not only to maintain efficiency but also safety. Solar systems are prone to corrosion, freezing and general plumbing issues. Your provider should be able to brief you on issues related to your particular system and also offer periodic inspections. With regular basic cleaning, routine check ups can be held even once in 3-5 years. Generally, opt for a passive system with no moving parts if you wish to minimize maintenance.
Installing a PV system is not difficult, however it is best left to experts. At Laupen we install solar electric systems in remodeling and green building projects. Generally the company that provides with solar system will take care of proper installation and get the system up and running. Or, as in the case of Laupen, who follow the design build model, it will be the contractors of your building project.
A solar electric system has many different components that are placed in different locations all over your home and have to be wired together properly. A stand alone/independent grid is the smallest in terms of component parts and a grid inter-tied with battery backup is the largest. The entire set-up will be done by the installers, after taking into account which system will work best for your needs and also fulfill requirements of state law, local building authority and power provider. There are a few things you need to ensure are done by the installers:
1. Checking the site of installation for year round incident sunlight, and more importantly – shading – in order to figure out which spot would provide optimal usage. Installers have their own equipment for doing this. Also, industry norms generally ask that homes in the northern hemisphere install solar panels facing the south or south-east and south-west directions. In some cases even east or west would do.
2. Installation of solar panels such that they are exposed to air, or well ventilated, to keep them from heating up.
Apart from installation, a PV system also needs periodic check ups to ensure efficiency. Ideally, this should be covered by your system provider. The solar panels or PV array is very low maintenance and you only have to inspect it at intervals to remove dust and debris.
PV system: 2 times
Solar electric system: 2 times
There are many factors that you should consider while buying a solar electric system or a Photovoltaic (PV) system, apart from its cost.
1. Electricity consumption: The US Dept. of Energy provides a simple formula to do this: Wattage per appliance X Number of hours it is used everyday. This will give you your electricity consumption in watts (usually kilowatts). The size of your solar electric system (the number of PV/solar panels) will depend on this consumption. It will also help you figure out if a solar electric system alone will fulfill all your electricity requirements.
2. Type of system: Contrary to popular opinion, system types do not depend on how much electricity they produce, but rather on how they supply this to your house. There are 3 options available –
a. A Grid Inter-tied System, when you want to remain connected to the grid, while offsetting your grid consumption by supplying it with electricity you produce;
b. A Grid Inter-tied System with Battery Backup to keep your house (or part of it) running even when the utility grid fails – a good option if you experience frequent outages.
c. An off-grid/independent System which is not connected to any grid and supplies electricity only to your home. This system requires making some adjustments, like learning to live with the energy you have.
Every system might not work or work differently in every state, depending on state laws.
3. Cost: It is difficult to have a standard cost for solar electric system, however, we can say that the price is generally up of $10,000 and the larger a system, the lesser the cost. Cost depends on the kind of system, kind of solar cells used in the system, your electricity requirements, amount of sunlight you receive, weather, etc. The best way is to find out your exact requirements and to invite bids from suppliers.
4. Suppliers: Finally, it all comes down to getting a good supplier. A ‘good’ supplier or installer is one who:
a. Is experienced in installing the type of system that YOU need
b. Is licensed to install solar systems
c. Provides you with options and advice on how to make the process efficient and reduce costs
d. Provides warranties and customer support.
August 13 2009
“When you start looking and keep your mind open – you’ll be amazed at the number of options you really have.”
This is something we learned on one of our custom homes projects. With green building, one really finds many viable and better alternatives if one looks long and hard enough. Take the case of this current project. One of the issues builders always face while building or remodeling is how to ensure stability of the house in a seismic zone like the one in Olympia. Using quality building material is, of course, a must — but not enough. Conventionally we’ve been using cement-based stucco to go apply an exterior finish to ICFs, (insulated concrete forms) but since it is cement-based, it normally tends to crack in the event of movement which happens to all houses here in all the Northwest. We found the answer in Oro coating.
Oro coatings is a synthetic stucco system, that can be used in place of traditional stucco to provide great coating, finishing, stability, adhesiveness and pliability which makes it the perfect stucco system for homes that are prone to damages during settling, due to seismic shocks and due to thermal expansion. However, most of all, 48% of this system is made from recycled or reclaimed materials and is 100% acrylic resin-based with no cement. One of the four components of Oro coatings is reclaimed rubber which contributes to its pliability. The entire system consists of a base, prime and top coat in 24 different colors, three textures and custom colors. We realized later that using Oro coatings also helps us gain credits for LEED certification. Our designer Tessa Smith had us router some clover details on the walls, which look absolutely fabulous with the Oro stucco. To know more about the Oro coatings, you can visit their website: http://www.orocoatings.com
The other great thing we learned on this project was related to insulation. Traditionally, attics are hardly ever heated. With this home, the attic was quite small with a shallow sloping roof. There were three things that needed to be taken care of. First, the heat recovery ventilator was to be installed inside of the attic, which meant additional insulation for its duct work. Secondly, because the attic was small, it would be impossible to have use blown in insulation due to limited access. This meant we would have to use batt style insulation installed between the bottom cords of the trusses. No matter how good of a job your installers do, with this type of installation you always get air gaps, which allows heat to escape. Thirdly, if the framing members, ( 2 x 4 bottom cords) are not covered completely, (which is always the case when you use batts), a thermal bridge is created. In the absence of proper insulation, heat escapes easily through the wood member. We solved all three problems together using 2 lb foam spray insulation on the underside of the roof deck. This created a conditioned space within the entire attic. Thus, there is no need for insulating the duct work for the ventilator, since the entire ventilator now lives with in the conditioned space. Next, it takes care of the gaps that will result out of the batt style insulation, since the foam expands as it is applied and penetrates into every gap in the framing members thus eliminating all air gaps. Thirdly, since it is five inches thick, it covers all of the plywood roof sheeting and the top cord trusses member thus eliminating the possibility of thermal bridging. All in all, we have a very tight house that should be very inexpensive to heat.
In the next few weeks the drywall gets installed as well as the exterior hand rails and window sills.