Q. My daughter rented an apartment where the landlord pays the utilities. It has no air conditioning and she's not allowed to get a portable unit. Is it legal to stipulate this?A. As odd as it may seem, it's not illegal for a landlord to prohibit the installation of a portable air conditioner, as long as this policy is announced in the lease or rental agreement. Landlords typically don't like portable units for two reasons: They are unsightly, and they substantially add to the cost of utilities, which naturally concerns landlords who pays the bills.The only limit on a rule of this type is a reality check: In areas where temperatures are high in the summer, few tenants will agree to rent an apartment knowing that they cannot escape the heat by buying a portable unit. When the landlord discovers that it's hard to find a tenant willing to agree to such a lease clause, he might change his mind. In your daughter's case, if she knew about the rule but signed a lease incorporating it anyway, she's bound by that clause.

Your daughter might try approaching the landlord to see if they can work out a compromise. If they can agree that the conditioner is likely to increase the utility bill by a certain amount during specified months, your daughter could offer to pay that sum.Q. I've lived in my apartment for five years. I've seen mold here and there throughout the years. This past week I found a huge spot behind a bedroom door, which just happens to be directly on the other side of the wall of where I've found mold on the living room wall. I asked my landlord to have someone test it since I'm afraid it might be coming from within the walls. He told me he plans to paint both rooms with paint that's supposed to prevent mold from growing on it.Is this a reasonable solution?A. Your landlord is taking a very shortsighted approach to this problem. From your description, it's likely that water from a leaky pipe, window, or roof is finding its way down the inside of the wall, seeping out and coincidentally encountering mold spores (which are prevalent in the air around us).

When mold spores find a renewing source of moisture, and particularly a little warmth, they set up house.As you can see, applying paint to the exterior of the wall won't address the real problem: the plumbing, roof or window leak that is seeping out of both sides of the wall. air handling unit typeGiven the appearance of another spot, you may be dealing with multiple leaks. air handling unit planThe sensible response is to get a good contractor in there to evaluate the situation and look for the leak.ac window unit size calculatorThings you need to know There are several types of air conditioners, each presents different problems regarding quieting, but generally most have some things in common. 1)  Older units are more noisy than newer units, mostly because they are near the end of their lives, while newer units are likely inherently quieter.

2)  Compressors make more noise than fans and when near worn out can be very difficult to quiet down. Replacement is the only option. 3)  Fan blades can make a lot of noise if coated with dirt through long use and can become imbalanced, causing bearings to go bad, adding to noise. Cleaning them can not only reduce sound, but add years to their lives. 4)  Sometimes it’s cheaper to replace a whole unit (even if it’s not yours!) than it is to try to remodel against the noise. These are difficult to quiet and many times it’s not the noise of the unit that’s the problem, it’s the noise that comes in when it’s OFF, because the air flows right through it from outside in and so does the sound of traffic, etc. If you removed the front vent panel and filter, you can see outside! Therefore, sound has an unimpeded path into the room. Such a condition can be helped by a shield fitted to the outside of the unit, thereby making the airflow and the sound take a right angle path into the air intake of the aircon.

Lining the shield with sound absorbing closed cell foam will really help reduce sound coming in. Your local sheet metal shop can make one for you if you give them the dimensions of the unit it to which it is to be fitted. These types move a lot of air and are usually pretty noisy, even when new. They tend to be large, because they cool (and sometimes heat) large areas. Because the sounds from them are loud and varied, (A combination of compressor and integral fan noise, as well as vibration), trying to soundproof them directly with material on them is usually fruitless and some sort of barrier/fence must be set up. If it is a roof mounted assembly, make sure there are adequate vibration pads under it to help reduce vibration transmitted into the roof. A noise barrier made of MLV can help reduce noise created and going down through the roof. If mounted on a concrete pad there will not be this kind of problem. Determine direction of the soundpath that is causing the problem and plan a fence barrier between it and the target of the sound.

(A bedroom window, for instance). Build a fence (no gaps in the slats!), at least 8′ high and 6′ wide that goes all the way to the ground as close to the unit as practical and line it with sound absorbent closed cell foam. 1″ thick is a good choice. If the soundpath is angling upwards, add a overhang to your fence to help block the path. If there is more than one soundpath, a fence in the shape of a “V” or even 3 sided like a “U” may be necessary. In some cases a boxed in area may be needed, complete with a roof to contain the sound. Access doors and ventilation will have to be planned for this type of solution. Some hints on how to baffle a noise source is here. Attic Fans and Air Conditioners: Some times it’s necessary to “Hang” these units from vibration mounts rather than set them on pads to reduce vibration to an acceptable level. When belts are used to drive the fans, problems can arise due to wear and aging of the assemblies and bearing blocks. Units that are comparatively quiet can become very annoying over time as loose parts begin to sound off.

Usually it’s necessary to add sound barrier and vibration absorbing mat around the installation to reduce sound transfer into the structure of the building. This is best done at initial installation rather than later when it will be much more difficult. Ducting needs to be covered with closed cell sound absorbing foam (not open cell foam), for sound and thermal insulation. Metal ducting needs to be physically isolated from the fan shroud or aircon unit with a flexible coupling. Otherwise is will re-radiate sound vibration along it’s length. Fiberglass or flexible ducting usually won’t have this problem, but will lose thermally if not insulated. Liquid soundproofing can be painted/sprayed on or in the metal ducting for even more sound vibration reduction. Vents are a problem if the design causes an air noise. To see if this is a problem, temporarily remove one to see if the sound level drops appreciably. Watch for vents to rooms that have a single common feed up through the wall- (or down through the floor to the ceiling below), if you can peer though the vent into the other side, it means sounds in one room will transfer to the other room.