Healer Unit Notes:  Priests, Imams, Medicine Men, Missionaries, and Surgeons heal in the same fashion. Miscellaneous Notes: Dancers Holy Dance (Medicine Man) Holy Dance (Warrior Priest) Healer Dance (Heals units)
1 Artillery benefits the most from healers.  A falconet is a huge investment but only has 200 HP (can heal 10 HP / sec).  In the colonial age, before veteran and other upgrades are available that reduce the effectiveness of healers, dopplesoldners, abus guns, and longbows are the top choices in terms of highest cost per HP.  At the bottom of the list are units that have a ton of HP but low cost.  A war wagon would be a decent example, 500 HP, but proportionally a relatively low cost per HP at only 150f and 150g.  In general, the better a unit’s armor the more effective healers will be. 0 0 0 0.0%
1 When a healer walks into range of the unit, it automatically begins healing (rates below).  1 210 473 0.4%
  2 104 235 0.7%
2 Healers, British Manors, and field hospitals cannot heal more than one unit at a time. 3 69 156 1.1%
  4 51 116 1.4%
3 Healers have to be close, their max range is 12.   5 41 92 1.8%
  2 Focus fire is the reason healers have failed to become effective.  Players simply do not have 400 HP of damaged units at a time when the gain would be most beneficial.   6 34 77 2.2%
4 Healers will not heal during combat.  Must wait till the battle is over and the unit is idle.   7 29 65 2.6%
  8 25 57 2.9%
5 Should a unit run away after a healer has started healing, the healing will stop. 3 The 4 Surgeon Colonial Age shipment grants 40 HP / sec for ~650 resources (average Age 2 shipment).  Master Surgeons are better, but cost the 650 resource shipment plus 300g a piece.  After the 4 surgeon age II card, priests are the 2nd best deal.  They are only 200 resources a piece and can be trained at the church without an HC shipment. 9 22 50 3.3%
  10 20 45 3.7%
11 18 40 4.1%
Explorer Healing (French HC Voyageur Shipment / Iroquois Fire Pit Secret Society Big Button Upgrade):  Explorers heal differently than regular healers.  Instead of an automatic heal, they receive a Heal ability which works as follows: 12 16 37 4.5%
4 Healers can be garrisoned inside TCs, Outposts, and Forts.  Inside TCs, they fire like villagers (including the Aztec Warrior Priest). 13 15 34 4.9%
  14 14 31 5.3%
1 Select the Explorer (French or Iroquois) 5 Field Hospital:  One of the least used buildings (for good reason) is the field hospital.  These can only be built by surgeons for 200 wood (have 1,500 hit points, offer no special technology, expensive, heal the worst in the game, and cost a shipment considering only a surgeon can build one).  Build in 10 seconds.  15 13 29 5.7%
    16 12 27 6.2%
2 Click the heal button (like the explorer's crackshot) and the cursor turns into a heart with a small circle around it.  17 11 25 6.6%
      18 10 24 7.0%
3 Click on the unit(s) desired to be healed.  a.) Field hospitals heal one unit at a time within their range of 20, at a rate of 3 hp per second.  19 10 22 7.5%
    20 9.5 21 7.9%
4 The healer walks to within range of the unit and begins healing (can be during combat).  b.) The hospital will not start healing a unit until it stops inside the heal area.  It will then heal that unit until its health is maxed.   21 9 20 8.4%
    22 8.5 19 8.8%
5 All units in the circle receive an hp boost, and all the same amount.  The sum of all hp regained is the limiting factor for a healer.  The magic number is 400 at a rate of 50 hp per second on each unit.   c.) Field Hospitals are not stackable.  If one injured unit is between 2 hospitals, only 1 will activate (won't heal 6 per second).  However, each hospital can work on 1 different unit.   23 8.1 18 9.3%
24 7.7 17 9.8%
    25 7.4 16 10.0%
6 The ability takes 120 seconds to recharge.  This time appears to be a reasonable value if the expectation is that the ability will be used between battles.   d.) If a surgeon is close to a field hospital, he will not work.  The hospital will heal at it's slow rate instead.   26 ---- 15 10.0%
27 ---- 15 11.0%
    6 Healing Upgrades and HC Shipments: 28 ---- 14 11.0%
7 The Explorers heal range is 12.   a.) Master Surgeons (Age II):   Surgeons heal 50% faster and train from both the church and field hospital. 29 ---- 13 12.0%
            30 ---- 13 12.0%
8 Should a unit run away after a healer has started healing (any unit in the heal area) the healing will be completed.  The healer will finish the heal animation and then walk towards the units.  b.) Mission Fervor (200F 200W):   Church Technology that grants healers 35% more hit points and increases speed by 15% 31 ---- 12 13.0%
    32 ---- 12 14.0%
          33 ---- 11 14.0%
  c.) Secret Society Technology (100C 200W) Fire Pit Big Button that grants the Iroquois War chief a healing ability 34 ---- 11 15.0%
Aztec Healer Dance:  The Aztecs can perform a unique dance at the fire pit that allows all idle units anywhere on the map to be healed at a rate of ~ 0.4% per villager dancing (the heal rate is not linear based on the number of dancers).       35 ---- 11 16.0%
d.) TEAM Cheap Priests:   Age 2 Russian HC Team Card that makes healers half price and train four times as fast (10 secs).
       
1 Dancers at fire pit: 20 7.9% HP healed per second.           Resources gathered per sec for calculating villager second costs
e.) Unction:  [1] Spanish Missionaries boost the attack of nearby soldiers 5% with a Range 24.  The aura is stackable up to 63%. Resource Resource Type Base Rate / Sec + % Rate Rate / Sec
   
Available Healers / Buildings that Heal         Coin Gather Rate Mining 0.60 0% 0.60
Unit Coin Cost Food Cost Wood Cost Hit Points Speed Armor Heal Range Heal Rate / Sec Population Build Limit f.) Voyageur:   French HC Card that grants Explorer healing ability   Food Gather Rate Berries / Cherries 0.67 0% 0.67
Wood Gather Rate Tree 0.50 0% 0.50
Aztec Warrior Priest 252[2] 0 0 360 4 10% range 12 10 1 10
Imam[3] 200 0 0 360 4 10% range 12 10 1 ---- Fishing - Whaling (canoes, etc.) Berries / Cherries Tree
Maya Medicine Man 0 200 0 200 4 10% range 12 10 1 4 Fishing - Whaling (fishing boat, warship) Farm Mango Grove
Medicine Man[4] 114[5] 0 0 200 4 10% range 12 10 1 10 Mining Fishing (canoes, etc.)
Priest[6] 200 0 0 360 4 10% range 12 10 1 ---- Mining - Dutch Fishing (fishing boat, warship)
Spanish Missionary 100 0 100 300 7 10% range 12 10 1 10 Plantation Hunting
Surgeon N/A 240 4 10% range 12 10 1 ---- Rice Paddy Mill
Master Surgeon[7] 300 0 0 240 4 10% range 12 15 1 ---- Rice Paddy
Monk (China) with Temple of Heaven Wonder 300 0 0 Varies 4.5 10% range 12 6 0 1[8]
Monk (Indian) 175 0 0 Varies 5 / 6 20% range 12 4 (6.7)[9] 0 2
Monk (Japanese) with Reiki Monestary technology 175 0 0 Varies 4.5 10% range 12 6 0 2
Field Hospital 0 0 200 1,500 N/A N/A 20 3 N/A 4
British Manors with Age 2 "Florence Nightingale" HC card 0 0 135 1,800 N/A N/A 12 5 N/A 20
India Sacred Field with Age 1 "Mystical Syllable" HC card 0 0 250 1,200 N/A N/A 10 8 N/A 2
 
Dancers at fire pit (spawn Medicine Man):[10] 20
Dancers at fire pit (spawn Warrior Priest):[11] 20  
 
Chinese Temple of Heaven Wonder:  Grants the Transcendence Ability
1 Heal all units on map up to 1,000 HP instantly (recharge 3:36)
Repairing:
1 Damaged buildings can be repaired by clicking the repair icon (a hammer) in the lower right hand corner.  Buildings cannot be under attack for 10 seconds and the player must have all of the required resources necessary to repair the building.  Once the resources are accumulated and the button is checked, the building starts repairing itself.
   
2 The repair costs are proportional to the amount of damage the building has taken.  It costs half as much to repair a building as it costs to initially build it.  For example, a TC has 6500 HP and costs 600W.  If the TC loses half of its hit points it will cost 150W to repair.  An important side note is that the rate of repair is 40 HP per second.  If the building comes under attack again the building stops repairs and refunds the unused resources to the players stockpile.
Docks and Ships:
An overlooked ability of docks is that they can repair idle ships.  Docks work like field hospitals, only better.  
 
1 One ship at a time
   
2 10 HP per second
   
3 The ships have to be next to the dock and not in battle.  
   
4 The Advanced Dock HC Shipment changes the repair rate to 20 hp per second.  
Download my "Unit Comparison" Excel Workbook for a complete unit to unit comparison of healers in the "Unit-Healer Comparison" worksheet.  
[1]
NOTE:

# Missionaries                Aura Effect (+ Damage)
1                                     5%
2                                     10%
3                                     16%
4                                     22%
5                                     28%
6                                     34%
7                                     41%
8                                     48%
9                                     55%
10                                   63%
[2]
NOTE:
Remember, the more gold technology resource rate improvements, the more the Warrior Priest will cost in equivalent villager seconds.  

Those same villagers could be on the gold mine gathering gold at an improved rate (opposed to dancing for 1 set value).
[3]
NOTE:
Ottoman
[4]
NOTE:
Iroquois & Sioux
[5]
NOTE:
Remember, the more gold technology resource rate improvements, the more the Medicine Man will cost in equivalent villager seconds.  

Those same villagers could be on the gold mine gathering gold at an improved rate (opposed to dancing for 1 set value). 
[6]
NOTE:
European Priests
[7]
NOTE:
With shipment, can build Master Surgeons from Church or Field Hospital.
[8]
NOTE:
The Age 4 Shipment "Walk the Rice Paper" allows a second Chinese Monk to be sent. 
[9]
NOTE:
Must research Improve the Age 2 Monastery technology Improved Healing (250G 250F) to increase healing to ~6.68 HP per sec (from ~4 HP per sec)
[10]
NOTE:
The villager second equivalent of the Medicine Man is based on how many dancers and the spawn time.  The more dancers on the pit, the cheaper the unit becomes.  The VS cost is compared to gold (like a mercenary).
[11]
NOTE:
The villager second equivalent of the Medicine Man is based on how many dancers and the spawn time.  The more dancers on the pit, the cheaper the unit becomes.  The VS cost is compared to gold (like a mercenary).