New HVAC installation to 1930s home rehab?

[Javier Cuevas Santos]

Planning a rehab for a 1930s 2-story 3 bedroom 1.5 bath house. Located in a Class B area with two surrounding elementary schools. Rehab is purely cosmetic and quoted around 5-7K to get it rent ready. Previously only had a ground floor furnace for heating and one window A/C unit for cooling. During inspection the furnace is found to be completely out of commission. I'm waiting for quotes from HVAC companies but I’d like to ask your opinion. Would you invest in a completely new HVAC system and duct installation where none exists? Or start out with fans, window units and heating units? I want to minimize the risk for fires since the bedrooms are carpeted. Goal is to get it rehabbed and rented ASAP. I welcome any advice!