• When considering the monthly mortgage cost and the operational costs such as heating, cooling, maintenance and insurance an ICF home or ICF/hybrid log home will be very close to or less than the total monthly costs of a traditional wood frame built home, plus the myriad of benefits associated with the super-structure. It is difficult to generically state the construction cost of a TWT structure compared to a conventional wood frame built structure because of the multitude of energy reducing options available, however, TWT construction cost, based on best available data to date, would be 5% – 15% higher than conventional wood frame construction.  The more energy reduction options utilized the higher the construction cost but also the greater the independence and utility cost reductions. Use of the single-sided ICF even without the use of hydronic wall tubes will provide a reasonable amount of energy efficiency and comfort benefits at little additional cost. The following is a partial listing of options ranging from lower to higher construction costs.
    • Construction utilizing the single-sided ICF without thermal tubing in the walls. The thermal amelioration will make the home more comfortable and help lower the energy usage beyond that of a traditional ICF structure.
    • Construction utilizing the single-sided ICF with thermal tubing in the walls and utilizing conventional heating sources such as a heat pump. The low temperature application as a result of the TWT will enhance the efficiency of the traditional heating systems, furthering lowering energy usage.
    • Construction utilizing the single-sided ICF with thermal tubing in the walls and utilizing hydronic solar heating. The low temperature application is ideal for a solar thermal hydronic system. At this point assuming you have properly controlled infiltration and air exchanges the structure is nearly self-sufficient with regards to heating, cooling and domestic hot water. The only addition is a small back-up heating system such as a heat pump or wood stove. Considering your heating, cooling and domestic hot water are materially addressed via the solar thermal hydronic system you will be using much less electricity. With an appropriately sized photovoltacic system you should easily be able to achieve net-zero energy status.

The return-on-investment (ROI) on your energy investment will vary depending on geographical location, regional cost of construction, the degree of energy reduction and energy independence elected is something that will need to be independently calculated for each location and structure.

Research is also underway to determine the feasibility of TWT construction utilizing a concrete masonry unit (CMU) (concrete block) or Architectural CMUs. Initial indicators suggest CMUs could be utilized in many TWT applications. 

  • The U.S. Department of Housing and Urban Development conducted a study, Insulating Concrete Forms: Installed Cost and Acoustic Performance published in 1998. The study found an increased cost of 3% to 3.5% in builders sale price. Please note this study is nearly 20-years old and substantial advances in ICF form manufacturing and installation have occurred.
  • In hurricane prone regions the cost becomes more comparable as the cost to meet hurricane standards for wood frame homes increases.
  • If financing the home it would be useful to develop a monthly cost of housing which reflects not only the slightly increased mortgage but also the reduced insurance and utility costs. What may be a $300 monthly utility bill could be reduced to $40 or $50 and insurance premiums may be reduced by 30% or more.
  • Another consideration is the likely continued increase in energy costs. Have your utility energy bills increased in the last 10-years? What will they be 10-years from now? Consider developing a 10 and 20 year model comparing the Thermal Wall Technology home to a conventional frame home and applying the monthly savings in energy and insurance. This will not only provide you the information it will also be beneficial when seeking financing. Your super-efficient home and near zero energy bills will also factor strongly on future resale value.
  • If you are planning on being off-grid then you will require a more robust photovoltaic solar collector system, battery backup system and solar thermal  hydronic system thus increasing the cost of construction. However, if off-the grid is your goal TWT will likely be your lowest cost option as the TWT efficiencies will reduce your heating and cooling equipment size and electric operational requirements, subsequently reducing the size and expense of the expensive photovoltaic solar collectors, inverter and battery backup system. 
  • There are several variables related to the cost of a TWT structure, the biggest being the degree of energy savings and independence you desire. A TWT structure that utilizes conventional heating sources without solar hydronic or photovoltaic solar electric will naturally cost less, however your energy bills will be higher and you are less energy independent. If you decided to go with the solar package of hydronic, photovoltaic solar electric and passive solar your energy bills will be near zero or you could be a net producer, however your construction cost will be higher. Also keep in mind if you plan properly you can have the option of adding solar later as your budget allows.

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