How long should my HVAC system last? February 24, 2011 â Art Avent, hvac advice. Among manufacturers, you are unlikeley to find anything definitive in writing on this question, but my personal opinion is that an electric heat pump & air conditioner SHOULD last 12-15 years & a gas furnace SHOULD last 15-20 years or more. Truth is, they last anywhere between 1 â 20 years.
Otherwise you may be asked to change your clothes and wear a hospital gown. It is best to leave all valuables at home. You may be asked to remove any jewelry, dentures, glasses, or any metal objects that may interfere with the CT scan.
The dye is usually given before the test through a vein (IV) in your hand or forearm. The dye helps the radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch you from another room. The test most often lasts 30 to 60 minutes, but may take longer. You may be asked not to eat or drink anything for 4 to 6 hours before the scan.