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Tales of a Modular Home Builder


Ductless Mini-Split Heating and Cooling Systems

Mini-Split Heat Pumps

I’d like to mention an option for heating and cooling a modular home.  It’s a ductless, mini-split heat pump.  The technology is not new, but it has improved so much that I’ve recently taken a closer look at it, and I like what I see.  In fact, we’re going to replace the HVAC system in our T-Ranch model home with one of these systems.

Why Today’s Mini-Split Heating and Cooling Systems are Better

In the past, heat pumps did not work well in the northeast because of the cold winters.  But heat pump technology has improved so much that these mini-split delivery systems can take care of your heating needs on all but the coldest winter days.  They also can keep you cool in summer.

Mini-split systems have also become more viable because today’s building code makes their job easier.  The “thermal envelope” of all homes built today is so energy efficient that heating and cooling systems have to work less to maintain a home’s temperature, even in more extreme temperatures.  Given that modular homes are especially well insulated and air sealed, they make it even easier to take advantage of mini-split systems.

How Ductless Mini-Split Heating Systems Work

Like central forced air systems, mini-split systems place the compressor and condenser outside the home. But they don’t need a single air handler in the basement or attic to distribute the conditioned air through a network of ducts.  Instead they use thin tubing that pumps refrigerant from the outside unit directly to a single wall mounted unit in each room.

Ductless mini-split heating and cooling systems place the compressor and condenser outside the home.

Ductless mini-split heating and cooling systems place the compressor and condenser outside the home.

Advantages of Mini-Split Systems

The use of individual units for each room allows flexibility in where the heating and cooling can be delivered.  Since one outdoor unit can be connected to as many as four indoor units, you can control the heating and cooling in several zones or rooms independently of each other.

Mini-split systems are less expensive than gas or oil central air systems when you factor in the cost to install insulated and well-sealed ductwork that meets the current energy code.  They also offer higher efficiency (up to 27.1 SEER).  Not only is the core technology of mini-split systems more energy efficient, but it also avoids the energy losses associated with the ductwork of conventional HVAC systems, even ones insulated to current energy codes.

The bedroom air handler for this mini-split system is hung above the painting on the wall.

The bedroom air handler for this mini-split system is hung above the painting on the wall.

Another advantage to mini-split systems is that they offer greater interior design flexibility.  You don’t need to enlarge walls or lose headroom in your basement or floor space in your attic to accommodate the ductwork.  The indoor air handlers can be hung on a wall or mounted on the ceiling.  Many systems include a remote control to adjust the system when it’s positioned on a wall or ceiling.

A ductless system is a great solution for building an addition to a home.  You get both heating and cooling for a reasonable price and you don’t need to hook-up to the existing system, which may not be sized for the additional load.

Disadvantages of Mini-Split Systems

There are a couple of disadvantages to mini-split systems.  One, of course, is that they can’t keep your home warm when it is bitterly cold, say below 10 degrees.  You will need a supplemental heating system for those days.  Electric resistance heat is a low cost solution.  Also, keep in mind that heat pumps are not able to bring a cold house up to temperature quickly.

The air handler in the living room for this mini-split heating and cooling system is hung on the wall.

The air handler in the living room for this mini-split heating and cooling system is hung on the wall.

Another disadvantage is that the indoor air handlers of a mini-split system are not silent, since they blow air through a grill.  But they also aren’t loud.  If you are particularly sensitive to a low level whoosh, find someone with an installed system so you can hear it for yourself.

Finally, take a close look at the photo posted here and make sure you’re comfortable with the appearance of the air handlers.  After all, you will likely have one in every room.

Weighing the advantages against the disadvantages, I think the mini-split systems are an excellent option.

For more information about heating and cooling systems, see Modular Home Specifications and Features and The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.

 

 

Wood and Pellet Stoves

Wood and Pellet Stoves Can Dry Out a New Home

Wood and pellet stoves are sometimes said to dry out a home too much and especially cause problems in new homes.  That’s why we instruct our customers to delay using a wood or pellet stove until the second heating season.  But the claim that wood and pellet stoves dry out a new home is both true and misleading.

What’s true is that wood and pellet combustion sends warm moist air from inside to outside the home through the flue.  This causes “replacement air” to enter the home from the outside.  In cold winter weather, this air is drier than the inside air.  However, today’s wood and pellet stoves don’t draw in more outside air than oil or gas boilers and furnaces.  So they don’t dry out a home more than a conventional heating system.

Wood and pellet stoves can cause excessively fast drying in a new home, especially if cranked up to a high temperature during the first heating season.

Wood and pellet stoves can cause excessively fast drying in a new home, especially if cranked up to a high temperature during the first heating season.

However, many people crank up the temperature of wood and pellet stoves much higher than hot water baseboard or warm air.  I’m someone who really appreciates the warmth of a hot wood stove after coming in from a cold day.  But it’s this high temperature that causes the wood and other materials in a new home to dry much more rapidly than a conventional heating system.  And it’s this excessive, rapid drying that causes an undue number of drywall cracks and nail pops as well as more warping, cupping, and shrinking of wood and other materials.

Warranty Coverage When Wood and Pellet Stoves Are Used

As a new homeowner, you need to know that this situation is not covered by the warranty of the modular manufacturer, dealer, or general contractor.  Wood floor vendors also don’t warranty against the excessive gaps between boards or splits in the boards that often result from the use of wood and pellet stoves.  This means that if you decide to use a wood or pellet stove during your first heating system, you will have to assume responsibility for any loss or damage caused by the excessive heat conditions.  On the other hand, waiting just one year before using these products at very high temperatures will help permit the wood and other materials in your home to dry slowly and normally.

For more information about the risks of using wood and pellet stoves during the first heating season, see Warranty Service for a Modular Home in my book The Modular Home.

No Blog Post This Week

The word blog on a yellow paper in a conventional typewriterLast week I made a presentation at the Modular Home Builder’s Association’s annual meeting.  I proposed some ideas about how to improve the industry.  I focused specifically on the relationship between the builder and manufacturer.

Since I need some extra time this week to catch up with my other responsibilities, I will not be posting to my blog.

Have a great week!

Building in the Winter

Protect the Ground When Building in the Winter

If you are building in the winter months in a region that requires protection against frost and snow, your general contractor should take some steps to reduce the impact of his work. He should blanket the areas he will be excavating before the work begins to minimize frost penetration. This might be done, for example, by covering the ground with hay. The excavated areas should stay blanketed until they are backfilled.

There are several extra steps to take when building in the winter.

There are several extra steps to take when building in the winter.

Keep the Access to Your Property Clear When Building in the Winter

The access to your site must be kept free of snow and ice. Even though bulldozers can move mountains, their tracks will just spin if they attempt to pull any substantial weight on ice. All snow and icy areas, even small light patches, must be plowed and sanded just prior to delivery. If it snows after the foundation is poured but before the home is set, the GC should remove as much of the snow as possible from the basement before the set. This is often easier said than done, however, and sometimes it’s impractical, especially when the slab has not already been poured.

You and your GC will need an agreement about who is responsible for snow plowing, shoveling, and sanding while your home is under construction. Since neither of you will know what the winter will bring in any given year, an allowance, with a reasonable rate per snowfall or per hour, is a fair way to handle it.

If your home will be delivered in the winter, try to have the foundation installed in the fall. The GC should then protect the foundation from the frost.

Take Precautions Pouring the Concrete Floor When Building in the Winter

When building in the winter in a cold climate, the GC should try to pour the floor before the temperature drops below freezing, as long as he can also protect it from the frost. If this cannot be accomplished, and the floor will be poured after the house is set on the foundation, the area must be covered with hay or in some other way protected from freezing immediately after the hole is dug. Any frost that remains after the house is set must be removed by heating the basement before the foundation floor is poured. Otherwise, the floor may crack substantially. If extensive frost or snow must be removed by heating the basement after the house is set, extra caution should be taken to prevent the house from absorbing the moisture.

Get the Heat Going When Building in the Winter

Contractors are less productive when they are cold, and many construction tasks, such as taping and painting drywall, cannot be done until a home is reasonably warm. Consequently, if you are building in the winter, the GC will need to get the heating system up and running quickly. He will be delayed, however, if the heating system is going in the basement and the slab cannot be poured because of frost. The installation will also be delayed if the electrical power is not immediately available. In these circumstances, the GC will need to supply temporary heat, which is more costly and less effective.

If you live in a climate with cold winters, you may want the contractor to add antifreeze to the heat loop. You should do this if you are away from home in the winter or if you have a drive-under garage, since leaving the door open on a cold day can cause the pipes to freeze.

If you are building during the spring, find out whether your community allows heavy equipment to travel on the roads during the spring thaw.

For more about building in the winter, see The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.

Modular Home Safety Tips

Modular Home Safety Tips

For the sake of everyone – family, friends, neighbors, and visitors – please observe these four modular home safety tips

Modular Home Safety Tips for Set day

A modular home set should be an exciting event. The last thing you want is for someone to be seriously hurt. With a crane that can weigh up to 150 tons, swinging a long boom and cable strapped to a module weighing 8 to 20 tons, there is a potential for injury. Friends, family, and other spectators should be kept away from the set crew and crane.

Modular Home Safety Tips for Immediately after the Set

The general contractor (GC) must do everything he can to ensure that the house is safe as soon as possible after the set. To protect against accidental falls, the GC should build a set of temporary steps to one of the doors, which will be used by the homeowners, contractors, suppliers, and inspectors until the GC builds finished stairs later. The GC should barricade or sheath over the rough opening framed in the floor for the basement stairs. If the home has a balcony overlooking a vaulted or cathedral area, the GC should install a temporary barricade or railing system to prevent someone from tumbling over the edge. A temporary cover should be secured to the top of the basement bulkhead. After the set, the site will have some materials that contain strips of wood with nails or staples.  These should be picked up and placed with the trash.

Modular Home Safety Tips for Alcohol and Drugs

The GC should have a zero-tolerance policy regarding alcohol or drugs on the job site.

No alcohol or drugs on the job site.

The GC should have a zero-tolerance policy regarding alcohol or drugs on the job site. The homeowners can support the GC in this regard by not bringing any alcohol to the site for the GC’s employees or subcontractors. If the homeowners supply alcohol, They could be liable for any resulting injuries that occurred on the job site.

Modular Home Safety Tips for Underground Utilities

Before digging, the GC should contact the appropriate authorities to determine if your property contains underground utilities (gas, electric, water, sewer, phone, or cable). If it does, he needs to have their locations marked so that they will not be disturbed during construction. And if you received instructions from a local, state, or federal board that governs wetland protection, the GC must follow the instructions exactly as written. For more about modular home safety tips, see The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.

Trash Removal

Trash Removal after Set Day

After the set, the site will have piles of plastic wrap that were removed from the modules.  The quantity of material almost always surprises customers and GCs without modular experience. The GC should dispose of all the material left over from the set immediately after it is completed.

In addition to the pile of trash created on set day, the button-up phase and construction of site-built structures will generate trash daily. Therefore, it is usually best if the GC uses a large dumpster to dispose of the trash.  If the site does not have room for a dumpster on set day, the GC can have one delivered the following day.

The best option for managing trash removal on the site is to use a dumpster.

The best option for managing trash removal on the site is to use a dumpster.

The GC may decide instead to use a truck or van to carry the waste from the site. In that case, he should provide a container or at least designate a location for everyone to place their trash. This can work as long as the GC regularly removes the trash; if he does not, your new neighbors may find trash being blown into their yards. You would probably prefer to get to know them under different circumstances.

Trash Removal when Packing to Move    

As you pack your belongings while preparing to move, you will undoubtedly generate a lot of trash. Resist the urge to use your GC’s dumpster. Even though you are paying for it, the GC needs all the room he can get for the construction debris. In addition, if your contribution fills the dumpster prematurely, you may receive a bill for an additional dumpster, which will cost a lot more than the extra time it would have taken you to use the town’s disposal services.

For more about trash removal, see The General Contractor’s Responsibilities for Building a Modular Home in my book The Modular Home.

Portable Toilet

This is a short but very important blog, especially in the minds of those who work on your modular home. Actually, it should be quite important to you as well.

A Portable Toilet is More than a Convenience

Like everyone else, contractors are most productive when they can conveniently use a bathroom. If they have to make a trip to the gas station or a restaurant, it costs time; and if they do not make the trip, they may be tempted to relieve themselves on your property. Eliminate this problem by renting a portable toilet until the plumbing is hooked up in your home. Then give the workers permission to use your bathrooms.

A portable toilet on site is not a luxury, but a necessity for everyone who works on your modular home.

A portable toilet on site is not a luxury, but a necessity for everyone who works on your modular home.

Don’t Wait To Place a Portable Toilet on Your Property

Your general contractor shouldn’t wait until after the set to put a portable toilet on your property.  Unless it will impede the movement of the crane and modules, the contractor should have it in place for set day. Not only will your general contractor and the set and crane crews benefit, so will your friends and family.

For more information about having a portable toilet on site, see The General Contractor’s Responsibilities for Building a Modular Home and Building a Modular Home on Schedule in my book The Modular Home.

Modular Homes Stand Strong

Two weeks ago I wrote about how modular homes stand up to severe weather, such as a tornado or hurricane.  In the past I described how one of our modules suffered only minimal damage when it fell off a trailer while we were setting the home.  I’d like to mention another example of the superior strength of modular homes.

In 1990 we brought a two-story modular home – the Whately 1 – from New York to Massachusetts where we erected it at the annual Springfield home show sponsored by the local chapter of the National Association of Home Builders.  Over 90,000 people visited the model.  After the show, we disassembled the modules and delivered them to our model home center where they were re-assembled.  Three years later we disassembled the modules yet again and moved them to a customer’s property where we reassembled them.

Our current Whately 1 two-story model home.

Our current Whately 1 two-story model home.

All together the four modules were each moved three times, assembled three times, and disassembled twice.  Each time they were assembled or disassembled they were lifted by a crane, which means they were picked up with a couple of thin straps five times.

A module being lifted onto the foundation by a crane using two thin straps.

A module being lifted onto the foundation by a crane using two thin straps.

If you’ve never seen a modular set, it is amazing how well the modules fare when they are lifted by the crane from the delivery carrier to the foundation.  This is especially true when you consider that each module weighs several tons, which makes the stress on the framing quite substantial.  Yet there was only minimal damage when the four modules of our old model home were craned into place for the last time. If a conventionally built home were lifted with a couple of thin straps even once, it would suffer substantial damage.

I will add one more observation.  As strong as modular homes were in 1990, todays modular homes are even stronger.  Food for thought!

For more information about the unique durability of modular homes, see Why Build Modular in my book The Modular Home.