Our goal is to have an easy-to-use-tool by the end of this year that allows one to calculate the business case of using GlassX for any given location, GlassX type, and building type. But on the projects to date we have found an average of 5-15 year payback on GlassX investment. Additional savings can be found from the reduction of HVAC assets.
It depends on what the energy costs are at the given location but we can say with confidence on average: with a proper solar design (where 60% of the façade is glass, 30% vision IGU glass 30% GlassX and good insulation of the envelope), can cut expenses on heating/cooling by around 30% to 50% per the year.
Project Location: Mannheim, Southern Germany (similar climate to North Eastern USA)
Building: Office building, 3 floors, 1115m2 each. With a quadratic footprint and 3m ceiling height is this roughly 300m2 south façade. Only this façade was renovated in the simulation.
Investment: the façade would be equipped with about 1/3 GlassX Store, i.e. 100m2. Taking a price of $600/m2 → $60,000 overall costs for GlassX elements.
Note: This does not include the retrofit of the rest of the façade i.e. about 2/3 triple glass insulation windows and thermal insulation of the opaque part. Neither included are the construction costs.
In 2010 there were 2743 HDD, and 266 CDD. Converted from C° to F°, this would mean 4937 HDD, and 497 CDD. This is somewhat in the range of Massachusetts.
The energy modeling project study established that the renovation with GlassX Store elements would save about 90MWh/y or 9,000L oil (or oil equivalent) for heating plus 25MWh/y electricity for cooling.
Taking an average heating oil price of $3.5/gallon, this would amount in about $7000 savings for heating per year. An electricity price (Boston area) of $0.16 /kWh would yield savings of $4000 for cooling per year.
The payback for the GlassX Store element is therefore quite easily achieved within 6 years* on this application.
*The costs for the normal windows, and the construction labour must however be added.