Charlie the Hillside HVAC mascot Bernese Mountain Dog
Delaware 302-738-4144
Maryland 410-398-2146

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HVAC Heating and Air ConditionOur professional staff is fully trained to install, maintain, and repair oil, natural gas, propane gas, and electric heating systems. This includes hot air, hot water, boiler, heat pump, and water heaters (both traditional tank and modern tankless on-demand water heaters). We've been successfully installing central heating solutions for over 60 years.

Hillside is capable of removal and replacement of fuel oil tanks, both old fashioned steel as well as modern Roth double-wall tanks.

We carry and service most name brand equipment including but not limited to: Armstrong Air, Thermo Pride, Peerless Boiler, LG and other ductless systems, Rinnai Tankless Water Heaters, Honeywell, Aprilaire, and Roth fuel oil tanks.

Our services extend to all types of indoor air quality, humidifiers, humidification, air cleaners, dehumidifiers. No matter your budget, Hillside has options ranging from economy to high efficiency.

Hillside is proud to sell and install all lines of new, modern, and remotely accessible thermostats made by Honeywell. Click Here for more information about controlling your thermostat from anywhere! Connect from smart phones or computers to manages temperatures according to your schedule.


Installation comparisons/chart of customer savings:

delaware hvac comparison

Hillside Maintenance Plans

Replacement Parts, Inspections, Tune-Ups, Adjustments, and more. See what plan is right for your needs.

Heating Maintenance Plan

Air Conditioning Maintenance Plan



Hillside Oil Tank Protection and Replacement Warranty

Hillside offers a tank protection program by TANK-GUARD®. This service is a corrosion and protection warranty giving "Peace of Mind" knowing the expense of replacing your heating oil tank will be covered if replacement becomes neccesary due to leaks.

Tank-Guard Proactive Heating Oil Tank Warranty


Hillside Credit Application

Establish an account by filling out this application. Credit billing customers receive 10 days for the same price as cash to the delivery driver. It's that easy!

Credit Application


Budget Sign-up Form

Hillside's budget plan stretches annual expenses into monthly payments. We use a simple formula...your annual expense with Hillside divided into the number of months remaining in our budget season. Plans designed specifically for your budget.

Budget Plans



  • I have dealt with other oil companies in the past and Hillside is far better. -James B.
  • I was surprised to find the skirting on my mobile home replaced properly. Other companies have not considered that necessary. Thank you. –Toni L.
  • Technician was excellent. Went above and beyond to teach me to replace filter. Also repaired cement around exhaust stack. Thank you! –Mary J.
  • I was impressed with everything about your company. I will not hesitate to refer you to my friends and family. –Peg B.
  • Have been a customer for many years. I always received prompt and courteous service. –Judy H.
  • Always a pleasure to deal with. I love the idea of talking to "live" people. Refreshing not dealing with automated system. -Laurie C.
  • Everyone at Hillside has been great over many years. –Jeff C.
  • People tell me I could get a cheaper oil company. I tell them I pay for excellent service. –Sara C.
  • I switched from another company to Hillside because your service has proven to be honest, caring, and professional. –Cheryl M.
  • We're very satisfied. Been with Hillside for 20 years. –J.E. K.
  • Hillside Oil Company is a full service fuel oil dealer with many years of experience. We decided to have them service our home heating unit and supply our fuel oil for that reason. We believe it was the right choice. Hillside has been servicing our home heating system and delivering our fuel oil for several years now. We have received prompt, friendly service on every occasion and highly recommend them.
  • We have been using hillside since we bought our house. We had them replace our Heat and AC and have used them for cleanings and tank fills. Every employee is courteous and professional. Prices are as good or better than most other companies. Would not choose anybody else.