Original HTM high thermal mass DIY passive solar earthhome greenhouse design

With well over 30 years of experience, TheNaturalHome is the original HTM thermic house designer. Please visit our website to learn why high thermal mass passive solar homes built with dry stack concrete block, mortared cinder block, poured-in-place concrete, or rammed earth walls are superior to ANY super-insulated HighR air-tight lightweight construction in ANY climate. Sustainable design, zero-energy, passive solar, HTM green homes can be free from mechanical climate control systems for truly independent living.

Conventional passive solar architecture relies on airtight HighR construction with light-weight materials to produce 'energy efficient' structures. This is the wrong path when you wish to have a healthy home with a clean indoor air environment. In order to attain the kind of energy efficiency ratings conventional architects claim, their structures must be sealed up as tight as a zip-lock baggie. Even with expensive air exchange heat pumps, venting fresh air into an airtight HighR home means losing most of your heated (or cooled) air. High thermal mass building materials allow Radiant heating and cooling energy to be stored within walls and floor so that you can vent air without 'losing' all of your heating or cooling comfort. The huge thermal mass acts as a giant battery constantly recharging with direct solar energy brought in through the windows in the winter and using the same moderating thermal mass 'Adobe home effect' to effectively cool in the summer with proper shading. Free heating and free air conditioning being the ultimate goal.

Conventional stick framing, log homes, strawbale houses, autoclaved aerated concrete, and insulated concrete forms ICF's are simply not feasible, passive solar, sustainable design materials because they don't effectively store and release radiant energy. Sandwiched insulation panels, interlocking extruded polystyrene EPS foam foundation blocks (ICF's) and trick insulated concrete block forms place the insulation on BOTH sides of the wall. Insulating the exterior of the foundation wall is standard and best practice, but insulating the foundation wall interior will prevent the release of stored Radiant energy back into the room. For truly sustainable passive solar homes, the wall and floor building material of choice is high thermal mass.

HTM green house designs don't require using alternative materials or techniques. We have always prefered to use poured-in-place concrete walls or better yet, concrete blocks for easy do-it-yourself dry stack block walls with surface bonding cement. Embodied energy from the initial construction may be higher, but by the time you factor energy savings over a lifetime of service, high thermal mass proves to be the lowest environmental impact overall. Plus, one must consider the personal value of a much more sustainable and Healthier indoor air environment with features like constant ventilation and indoor gardening.

Commercial do-it-yourself HTM construction details can cut building costs by well over twenty percent, as compared to conventional stick-frame residential house plans. In every part of the world, corner markets, garages, gas stations and warehouses are built with concrete and block for best economy, durability, longevity, and ease of maintenance. In parts of Florida, nearly every home is cinder block-built to avoid termites, rot, and mitigate tropical storm damage.

Truly sustainable HTM passive solar home designs require a holistic approach, incorporating all core aspects for non-electric passively independent success. Picking and choosing HTM design components based solely on aesthetics will negatively affect passive solar function. Form follows function for best performance, economy of construction, optimal health, and personal comfort. We trust any hybrid HTM will function much better than a conventional home, but dropping a critical design element such as wing insulation, earthtubes, or not collecting 'excess' solar energy will ultimately affect passive solar performance.

The Natural Home no longer provides any paid design work, architectural rendering, or engineering services, but our free HTM guidebook is maintained online for green home building construction and design research. We cannot offer any trade referrals to professionals fluent in this specialty, but any respectable 'commercial' contractor is capable. Nothing exotic about the construction. Just avoid conventional stick-frame residential builders since they are rarely as comfortable with HTM designs. Best wishes for your project.