Zero Energy Retrofits

Benefits of Remodeling Existing Homes to Zero or Near Zero

Remodeling or retrofitting existing homes so they become significantly more energy efficient is as important as building new zero energy homes; and more and more homeowners are showing that you can indeed remodel an older home to Zero. Here are some of the many benefits to energy remodeling older homes towards zero:

  • Even low to mid-cost energy remodeling can save homeowners a lot of money in energy bills.
  • Energy remodeling curbs carbon emissions.
  • Energy remodeling improves the indoor environment, health and comfort of the occupants.
  • Remodeling existing homes creates jobs by employing a wide range of workers, with good paying jobs.
  • Remodeling and revitalizing existing homes has positive effects on neighborhood and community. Even vacant foreclosed properties are being renovated into zero energy homes in Milwaukee. See the Fox News report on this project.


Case Studies

Four Steps to Getting Started

Follow these four steps as outlined or use them as a guideline for a more flexible approach.

1. Select a Certified Energy Auditor, Energy Assessor or Energy Consultant. Your first step should be to hire a professional energy consultant with solid credentials, references and experience in conducting residential energy audits. They should be able to:

  • Conduct a blower door test and systematically identify air leaks during the testing.
  • Do thermal imaging of the home with an infrared (IR) camera.
  • Assess the current level of insulation of the shell and estimate its R-value.
  • Assess the quality of the windows and doors and estimate their insulation or U-value.
  • Assess a year’s worth of utility bills and assess the energy efficiency of appliances, water heaters and the heating and cooling system.
  • Assess the energy efficiency of the lighting.
  • Assess the occupant’s energy-use habits and lifestyle.
  • Assist the occupant in setting an ambitious, yet practical and affordable goal for overall site energy reduction

It is recommended that you do ample research, and get estimates from more than one qualified Energy Auditor or Consultant. Ask for samples of previous energy audits and references from their customers.

2. Select A Contractor Experienced in Zero and Near Zero Energy Retrofits. Selecting a contractor that is knowledgeable and experienced in remodeling homes for near zero energy is critical. Since creating an exceptionally air tight house is so critical to reaching the Zero Energy Goal, it is important that the contractor is very well versed in retrofitting for a tight building envelope. In addition, he should be knowledgeable and have experience with:

  • A variety of insulation materials and strategies for adding insulation to an existing building in a cost-effective manner.
  • Blower door equipment to identify all the air leaks in the home. Blower door testing should be used by the contractor during the retrofitting process to find any air leaks, systematically reseal them, and re-check them as many times as needed to reach your air tightness goal
  • The most cost effective, most energy efficient windows, heating and cooling systems, ventilation systems and appliances.
  • It is best to interview at least three qualified contractors, have them evaluate your home, and have them give you a preliminary estimate, as part of the selection process.

3. Select a Expert in Energy Modeling. Work with your contractor to select an energy consultant or building engineer who specializes in energy efficient home retrofits, to conduct energy modeling on the proposed alterations and upgrades for the home. Energy modeling analyzes a building’s energy-related features in order to project energy consumption of a given design. It serves as an important tool for understanding the requirement of efficient retrofits during the design process. The energy modeling will help you and the contractor set specific objectives for reaching the Zero or Near Zero Energy Goal in your home as cost effectively as possible.

The energy modeling objectives should include:

  • Degree of airtightness to be achieved. For example: between 4.0 a air changes per hour (ACH) at 50 Pascals pressure is an ambitious goal for minor energy remodels and under 2.0 ACH is a common goal for a full zero net energy remodel.
  • The necessary insulation to be installed to achieve the desired R-value of the building shell.
  • The insulation value, or U-value of the windows to be achieved (either through adding new low U-value windows, adding energy efficient storm windows, and/or adding insulated honeycomb shades.)
  • The energy efficiency of the appliances, ventilation system, heating and cooling system, and lighting that will be required to reach Zero or Near Zero Energy Goal.
zero net energy modeling insulation

One of the things energy modeling does is determining insualtion values.

4. Select a Designer or Architect Experienced in Zero or Near Zero Energy Remodeling. After you have conducted an energy audit and energy modeling, you are ready for a designer that can put the plans on paper. The designer takes all of the specifications from the energy audit and modeling and integrates them into a complete design document. This helps the contractors and subcontractors in making their estimates and completing the work. For example, if the R-value of the walls, ceilings and floors is specified, the insulation subcontractors can make their estimate based on R-value to be achieved.

It is important to note that from the very beginning, and throughout the retrofitting process, the homeowner, energy consultant, the contractor and the architect or designer should work as a team as much as possible.

Long Term Planning Towards Zero Energy Remodeling

Many people have financial plans for retirement that are implemented over many years, even decades. Making a long-term energy conservation remodeling plan for your home is a great way to implement measures that keep you on the path to remodeling your home “Towards Zero” without over-taxing your budget. A “Towards Zero” Remodeling Plan could involve estimating the lifetime of appliances, heating and cooling systems, roofs, siding, windows, and doors, and putting these estimated lifetimes into a replacement timeline with a budget for each item – so you can gradually renovate “Towards Zero” in a systematic, affordable way

19 Practical, Cost-Effective Steps for Remodeling to Near Zero

Start by considering the most cost effective energy saving steps first. The following steps are listed roughly in order from least to most costly depending on the specific circumstances in your home:

1.  Sealing and tightening all obvious air leaks around windows and doors with transparent caulking.

2.  Turning off and unplugging all electronics when not in use and/or using energy strips for all electronics, so they can easily be disconnected when not in use.

3.  Gradually replacing all the light bulbs with compact florescent or LED light bulbs, as existing bulbs need replacing. Use LEDs for the light fixtures that get the most use.

4.  Adding low flow showerheads and faucets to reduce hot water use.

5.  Drying clothes on clothes hangers, drying racks, or clothes lines as often as possible.

6.  Adding motion detector switches in high use rooms such as teen bedrooms and bathrooms where lights tend to be left on.

7.  Replacing existing electronics and appliances with the most energy efficient models when they need replacing or upgrading.

8.  Air tightening the shell of your home (the floors, ceilings, windows, doors, outlets and walls) with transparent caulking while a blower door is running to seal all air leaks in order to lower your Air Changes per Hour to near 4 ACH@50 Pascals, or even lower depending on your objectives.

9.  Installing low-e storm windows, which can save up to 20% of the heat lost through the windows.

10.  Installing tight fitting insulated shades or insulated shades with tracks with an approximate R-value of 3 to 4, which could more than double the R-value of the existing older windows.

11.  Adding blown-in ceiling insulation, which often is an easy and inexpensive measure.

12.  Blown-In Ceiling Insulation

13.  Installing floor insulation or basement wall insulation.

14.  Installing an Energy Recovery Ventilation System or Heat Recovery Ventilation System to provide a continual supply of fresh filtered air in any home that has been so well sealed that the ACH is near or below 4.0.

15.  Installing a ductless heat pump mini-split heating and air conditioning system, which is very energy efficient and easy to install.

16.  Installing a solar hot water system or a heat pump hot water heater to reduce hot water costs.

17.  Adding Insulation to Existing Walls

18.  Installing added insulation in the existing walls by blowing it into the walls, or by removing the siding and adding it to the outside of the wall before re-siding.

19.  Installing or leasing a solar PV system. If it is available in your state, using Sun Run or other similar leasing system, minimizes the cost of the solar PV and makes it one of the most cost-effective of the steps listed.

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