Confusing Terms

Even professionals often confuse the term "vapor barrier" with the term "moisture barrier". Here is the difference:

• Moisture Barrier - Moisture barriers (like Tyvek, for example) are properly installed on the exterior of a frame wall, directly on top of the sheathing, and under the siding. Moisture barriers help prevent water from entering the wall cavity.

• Vapor Barrier - Vapor barriers, typically a polyethylene plastic sheeting, are installed on the inside of a frame wall between the studs and the drywall. Vapor barriers help prevent water vapor from the interior of the house filtering through the wall and condensing on the warm side of the insulation. Wet insulation is a no-no.

In a typical household, heating and cooling make up well over half of the total energy use. Insulation and sealing up the "building envelope" from outside air can drastically reduce energy consumption. Next in line should be selecting energy efficient appliances and heating/cooling units.

Many older homes come equipped with radiator heat and an older gas-fired boiler, but no air conditioning. Chances are, you will be either upgrading or replacing the HVAC system(s) in your renovation.

Efficiency

Great strides have been made in HVAC efficiency. For air conditioners, efficiency is measured by a Seasonal Energy Efficiency Ratio (SEER) number. The higher the number, the more efficient the unit is (and usually the more expensive the unit is). Purchase the highest rated unit you can afford.

HVAC Types

Forced Air Furnaces
When it comes to heating, the newest energy efficient forced air furnaces approach the mid 90% range - this means that over 90% of the energy created by the furnace is captured for heating your home.

Insulating the area behind a "knee wall" can help save on energy costs. Note the new vapor barrier installed on the interior of the stud wall.

Many historic homes in Des Moines were constructed before air conditioning was invented. Prior to the age of freon, people used various "passive" methods for cooling themselves during the hot months of the year.

The "Natural Living Des Moines" blog has a great post on some easy ways to stretch your cooling dollar. Here are their ideas (with some commentary by me):

• Open the Windows - In addition to what they say, if your windows are the double hung type (both the top and the bottom sashes are operable) open the bottom one halfway and pull the top sash down halfway. This will allow hotter air to escape out the top and cooler aire to enter through the bottom openings.

• Keep the Air Moving - Ceiling fans are a great low impact alternative to lower the air temperature at your skin. Air moving over your body facilitates the cooling effects of evaporation.
• Don't Make the House Warmer - Avoid running appliances that create heat like ovens, light bulbs, computers, stoves, and dryers (your refrigerator actually creates heat in the kitchen, but don't unplug that one). Try grilling your dinner outside and hanging your clothes to dry in the sun.
• Close Off Unused Rooms - No use wasting energy conditioning rooms that you're not in on a regular basis.

Once the drywall is installed, taped, and painted, the cabinets placed, tile laid, and all the fixtures are on site the systems finishing stage begins. You will call back your electrician, plumber, and HVAC contractor to install the final pieces of each trade and complete the contracted work. You should hold back a reasonable portion of the contract payment until the finish work is completed to your satisfaction.

The HVAC finish work includes placing the fan units and condensers, charging the air conditioner if required, and placing the vent covers.

Many older homes are outfitted with “knob and tube” wiring where individual wires are supported (and kept from touching each other and the building) by ceramic fittings. This method of wiring is not inherently dangerous unless the fittings or wires are damaged - as is often the case during renovation. Knob and tube wiring also has no provision for the “grounding” wire required for three-prong outlets. Today’s technology consists of an insulated cable that contains three or more wires including at least a “hot” wire, a “neutral” wire, and a ground wire. In BX-type cables (armored cable), required in some situations, the wires are contained within a metal sheathing that provides additional protection. This insulated wire is easy to install and provides a high degree of safety. All new wiring must meet the current electrical code.

Installation

A licensed electrician must install all wiring for outlets, fixtures, switches, and appliances. Anyone may install telephone, cable, and structured data lines. You can save some money on electric by running these wires yourself – phone lines may be “chained” together, but each cable and structured data outlet should have a “home run” to the basement where they can be managed individually or hooked into a home automation system.

The rough-in phase for your electrical system includes running all the wiring and installing all the junction boxes necessary to implement your electrical concept plan. The wires will terminate at the breaker box, but will not be made "live" until the electric finish later on in the process.

It is sometimes useful to walk through the building with the electrician who will be performing the installation. This will give you a chance to make any last-minute corrections or additions.

The electric system is the most flexible of the three major systems. While your electrician must follow applicable codes that dictate where wires may run, it is generally possible to get a fixture or outlet pretty much anywhere you want. It is much easier, however, to place fixtures and outlets in frame walls than it is to place them in masonry walls. If you must have an outlet in a masonry wall, the brick has to be chipped out to allow space for the wiring and the outlet or fixture. Then the wall is repaired to hide the wiring. I generally discourage surface-mounted wiring and fixtures, even when allowed by code, unless there is not other alternative.

Your plumber deals with all the PVC (plastic), copper, flexible, and cast iron pipes in your house. This includes the water supply, drains, vent stack, sewer connection, hot water radiators, and natural gas. As with all your other contractors, make sure that your plumber has experience working in renovations, particularly if you are pursuing historic tax credits.

It is important to coordinate between the plumbers and carpenters - there may be unique situations where walls, chases, and soffits must be framed to create space for waste stacks, plumbing traps, and vents.

Heating/cooling (HVAC), electric, and plumbing are generally considered the "major" building systems. Related systems include, but are not limited to the following:

• HVAC
  • Whole house vacuum system

  • Humidifier and dehumidifier
  • Mechanical venting (attic vents, bathroom vents)
  • Radiant heating
  • Make-up air
• Electric
  • Security system

  • Backup generator
  • Solar cells
  • Low voltage systems (undercabinet lighting, telephone, intercom)
  • Cable/satellite
  • Speaker wiring
  • Structured wiring (Cat-5)